A suspension containing nicosulfuron and its preparation process

Abstract

This invention provides a compound herbicidal composition comprising mesotrione, atrazine, and cypermethrin, which is prepared as a suspension concentrate. By using specific adjuvants, it solves the problems of decomposition of mesotrione and cypermethrin, and crystallization of atrazine. The product is stable for a long time, has a long shelf life, and can also broaden the herbicidal spectrum and improve the herbicidal effect. It can solve the problem of weed resistance to mesotrione single agent and binary compound products.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of pesticide preparation, in particular to a suspension concentrate containing mesotrione and a preparation process thereof. BACKGROUND

[0002] Corn is one of the three major crops in China, but it is seriously harmed by weeds. In related technologies, corn field herbicides use conventional active ingredients such as atrazine, nicosulfuron, mesotrione, alachlor, acetochlor, and isopropylamine alone or in combination. Pre-emergence herbicides are generally acylamide herbicides and atrazine, and post-emergence herbicides are generally two or three-component combinations of atrazine and nicosulfuron, mesotrione, etc.

[0003] Currently, herbicide products containing mesotrione used in corn fields mainly use mesotrione + atrazine, and the dosage form is mainly oil suspension concentrate. On the one hand, the cost of oil suspension is high; on the other hand, long-term use of mesotrione and atrazine combinations has caused crop resistance problems. Therefore, the weed killing rate of two-component products mainly containing mesotrione cannot meet the crop weed control requirements. Other herbicide products containing mesotrione mainly use multiple combinations (mainly suspension concentrates and oil suspension concentrates), and the production cost, packaging cost, and processing cost of such multiple combinations are relatively high, and the processing technology is relatively complex. However, as one of the most commonly used herbicides in corn fields, atrazine has drawbacks such as large application amount, sensitivity to surrounding crops, easy drug damage, water pollution, long residual period, etc., which has caused environmental protection agencies from all walks of life to call for the gradual elimination of atrazine, causing atrazine to be in the banned wave.

[0004] Mesotrione is a triketone compound, and the pure product is a light yellow solid with a melting point of 165.3°C (with decomposition), a water solubility (20°C) of 0.16 mg / mL, and decomposition problems in neutral and weakly alkaline environments. Mesotrione has high activity and low use amount, and the use time must be early. The control effect on gramineous weeds is poorer than that on broadleaf weeds, such as Digitaria sanguinalis, Eragrostis curvula, and Setaria viridis.

[0005] Ametryn is a selective triazine herbicide with internal conduction, and the pure product is a colorless powder with a melting point of 86.3-87°C. The solubility in water is about 200 mg / L (25°C), and it is easily soluble in organic solvents. It is stable in neutral, slightly acidic, or slightly alkaline media, but it is hydrolyzed to 6-hydroxy derivative with no herbicidal activity in strong acid or strong alkaline media. The ametryn single-agent product is mainly 500 g / L suspension concentrate, but it is easy to cake during processing and to crystallize during long-term storage, causing product quality problems. The registered ametryn combination preparations are all wettable powders, which have high processing costs, are easy to produce dust during processing, and are easy to cake and reduce efficacy during long-term storage.

[0006] Lasso is a colorless crystalline solid with a melting point of 166.5-167.0℃, and its solubility in water (25℃) is 171 mg / L. It is easily hydrolyzed in an acidic environment.

[0007] Patent applications in the prior art have disclosed herbicidal compositions of mesotrione, ametryn and cyanazine, such as CN107897185A, which mainly focuses on the synergistic effect of the active ingredients. Although a suspension concentrate formulation is also disclosed, no quality control indicators of the formulation are disclosed. It is found that the formulation cannot maintain long-term stability, mesotrione and cyanazine have high decomposition rates, and ametryn is prone to crystallization, resulting in particle settling. SUMMARY

[0008] The purpose of the present application is to provide a herbicidal composition comprising mesotrione, ametryn and cyanazine, which is prepared into a suspension concentrate. The processing cost is lower than that of oil suspension concentrate and wettable powder, which can overcome the problems of decomposition and crystallization of active ingredients, and can also expand the herbicidal spectrum and improve the herbicidal effect. It can solve the problem of resistance of weeds to mesotrione single agent and two-component complex products.

[0009] Unless otherwise specified, the percentage in the present application refers to the weight percentage.

[0010] The suspension concentrate of the present application comprises the following ingredients: mesotrione 4%, ametryn 30%, cyanazine 14%, anhydrous citric acid 0.55-0.65%, block polyether 1-3%, methyl acrylate copolymer 1-3%, and further comprises surfactant 1-3%, thickening agent 0.1-2.5%, antifreeze 3-7%, preservative 0.1-0.3%, defoaming agent 0.2-0.3%, and deionized water to 100%.

[0011] The surfactant is phenylethyl phenol polyoxyethylene ether sulfate 1-2% and phenylethyl phenol phenyl polyoxyethylene polyoxypropylene ether 0.2-0.5%.

[0012] The thickening agent can be one or a combination of more than one of xanthan gum, magnesium aluminum silicate, gelatin, sodium carboxymethyl cellulose, polyvinyl alcohol, modified starch, hydroxyethyl cellulose, bentonite, silicon dioxide, and white carbon black; the antifreeze can be one or a combination of more than one of ethylene glycol, glycerol, polyethylene glycol, sorbitol, and urea; the preservative can be one or a combination of more than one of sodium benzoate, sodium salicylate, propionic acid, and sorbic acid; and the defoaming agent can be an organic silicon defoaming agent.

[0013] The suspension agent of the present application adds a specific amount of anhydrous citric acid to prevent the decomposition of mesotrione and cyanazine, and the addition ratio should be between 0.55-0.65%. If the addition amount is too low, mesotrione will decompose, and the final product will also be caked; if the addition amount is too high, cyanazine in the product will hydrolyze, the system will change, and then it will directly cake during the heat storage process.

[0014] In another aspect, the suspension agent of the present application also adds benzene ethyl phenol phenyl polyoxyethylene polyoxypropylene ether and high molecular weight methyl acrylate copolymer to provide a special dispersion structure system and steric hindrance for the product, and cooperate with a specific amount of anhydrous citric acid to keep cyanazine stable in a weak acid environment.

[0015] The addition of block polyether in the suspension agent of the present application can inhibit the crystallization of ametryn particles to ensure the stability of the product. After two years of experimental observation, no crystals are precipitated from the product.

[0016] The preparation method of the suspension agent of the present application comprises the following steps:

[0017] (1) water is added to a stirring kettle, stirring is started, and auxiliary agents are added and stirred uniformly, and then mesotrione, ametryn and cyanazine are added and stirred uniformly;

[0018] (2) the material is placed in a first sand mill for coarse grinding, and the coarsely ground material is stored in a first transfer tank;

[0019] (3) when the material in the first transfer tank reaches a certain amount, the material is transferred to a second sand mill for fine grinding, and the finely ground material in the second sand mill is stored in a second transfer tank;

[0020] (4) when the material in the second transfer tank reaches a certain amount, the material is transferred to a third sand mill for fine grinding, and the finely ground material in the third sand mill is stored in a third transfer tank;

[0021] (5) after fine grinding to D90≤7μm, the material in the third transfer tank is transferred to a mixing kettle, and stirring is performed until uniformity to obtain the finished product.

[0022] By adopting the above technical scheme, the present application has the following beneficial effects:

[0023] 1. The suspension agent of the present application has simple processing mode and low cost, and uses water as the main carrier, which is friendly to the environment.

[0024] 2、The suspension agent of the present application uses specific adjuvants to solve the problems of decomposition of mesotrione and cyanazine, crystallization of ametryn, etc. The product is stable for a long time and has a long shelf life. After 14 days of storage at low temperature of-7℃ and high temperature of 54℃, the product does not decompose, clog, flocculate, etc.; after one week of freeze-thaw experiment at low temperature of-25℃, the product is still stable and normal, and all indexes meet the parameter requirements.

[0025] 3、The suspension agent of the present application can be used for controlling grasses and broadleaf weeds, and has good control effect on Digitaria sanguinalis, Eupatorium odoratum, and Cynodon dactylon, which is superior to the use of two or three components of post-emergence herbicide ametryn and sulfometuron-methyl, mesotrione, etc.

[0026] 4、The suspension agent of the present application has strong resistance to rainwater scouring, long persistence, fast effect, high efficiency and low residue, and good safety to subsequent crops. DETAILED DESCRIPTION

[0027] The technical solutions of the present application will be described below in conjunction with examples, obviously, the described examples are part of the examples of the present application, rather than all the examples. Based on the examples in the present application, all other examples obtained by those skilled in the art without creative labor are within the protection scope of the present application.

[0028] All the products used in the following examples are commercially available, in which the methyl acrylate copolymer is DISPER D1000, and the block polyether is DS9100 polyurethane polyether E0 / P0 block.

[0029] Example: 48% mesotrione·ametryn·cyanazine suspension agent

[0030] Mesotrione: 4%

[0031] Ametryn: 30%

[0032] Cyanazine: 14%

[0033] Anhydrous citric acid: 0.6%

[0034] Benzyl phenol polyoxyethylene ether sulfate: 2%

[0035] Benzyl phenol phenyl polyoxyethylene polyoxypropylene ether: 0.5%

[0036] Methyl acrylate copolymer: 3%

[0037] Block polyether: 2%

[0038] Xanthan gum: 0.15%

[0039] Magnesium aluminum silicate: 1%

[0040] Ethylene glycol: 5%

[0041] Sodium benzoate: 0.2%

[0042] Organosilicon defoamer: 0.3%

[0043] Replenish with deionized water to 100%.

[0044] Preparation method:

[0045] Weigh each component according to the above composition. Add the measured amount of water to the mixing tank, turn on the stirrer, add the adjuvants and excipients, and stir until the components are fully mixed in the water. Add the measured amounts of nicosulfuron, atrazine, and cyanazine technical grade in sequence. Do not stop shearing during the feeding process to prevent the solids from rapidly settling and clumping after being added. If floating solid powder is found on the liquid surface, stop feeding and continue shearing until all the solid powder is dispersed before continuing feeding. After all feeding is completed, continue shearing for about 30 minutes. Reduce the shearing speed to the minimum until all the mother liquor has passed through the sand mill before stopping shearing to prevent the technical grade from settling.

[0046] Open the water inlet valve of the first sand mill's chamber jacket and start the pneumatic diaphragm feed pump. Approximately 10 seconds after starting the pneumatic diaphragm pump, start the sand mill for coarse grinding. The material coarsely ground in the first sand mill is stored in the first transfer tank. When the material in the first transfer tank reaches a certain quantity, it is transferred to the second sand mill for fine grinding. The material finely ground in the second sand mill is stored in the second transfer tank. When the material in the second transfer tank reaches a certain quantity, it is transferred to the third sand mill for fine grinding. The material finely ground in the third sand mill is stored in the third transfer tank. The flow rate is controlled by adjusting the corresponding pneumatic diaphragm feed pump; the flow rate of the mother liquor through the fine mill is no greater than that through the coarse mill, and the fine mill discharge rate is 3.3 kg / min.

[0047] After fine grinding, the material in the third transfer tank is transferred to the mixing vessel and stirred until uniform to obtain the finished product.

[0048] The finished products were sampled and tested, and the relevant control indicators are listed in Table 1.

[0049] Table 1 Control Indicators:

[0050]

[0051] Comparative Example 1:

[0052] To investigate the effect of anhydrous citric acid content on formulation performance, a comparative example was prepared based on the above examples, differing only in the anhydrous citric acid content. The contents of nicosulfuron and cypermethrin, as well as the product flowability, were measured after heat storage (54±2℃, 14 days). The experimental data are listed in Table 2 below.

[0053] Table 2

[0054]

[0055]

[0056] The test data show that when the addition amount of anhydrous citric acid is 0.6%, mesotrione and cyanazine are not substantially degraded, the preparation maintains normal fluidity, and no obvious solid particles are generated.

[0057] Comparative Example 2

[0058] To detect the effect of the block polyether on the crystallization of ametryn, ametryn suspensions were prepared according to the above examples as comparative examples, with the difference that the block polyether was replaced by other surfactants. The particle size of ametryn crystal was determined after storage at different temperatures. The test data are shown in Table 3 below.

[0059] Table 3

[0060]

[0061]

[0062] The test data show that the block polyether DS9100 can inhibit the particle size growth of ametryn crystal at normal temperature, cold storage and hot storage, and the preparation does not have particle sedimentation. Other surfactants have poor effects.

[0063] Field efficacy test

[0064] Controlled object: annual weeds, including Digitaria sanguinalis, Echinochloa crus-galli, Eleusine indica, Cyperus difformis, Commelina benghalensis, Stellaria media, Acalypha australis, Alisma plantago-aquatica, and so on;

[0065] Tested agent

[0066] Tested agent: 48% mesotrione·ametryn·cyanazine SC prepared in the examples

[0067] Controlled agent: 10% mesotrione SC, 40% cyanazine SC, and 80% ametryn WP

[0068] Application method: directional spraying with water

[0069] Test results

[0070]

[0071]

[0072] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, and are not intended to limit the present application; although the present application has been described in detail with reference to the above embodiments, those skilled in the art should understand that the technical solutions recorded in the above embodiments can be modified, or some or all of the technical features can be replaced by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A suspension concentrate comprising mesotrione, characterized in that, By weight percentage, containing mesotrione 4%, ametryn 30%, cyanazine 14%, anhydrous citric acid 0.55-0.65%, block polyether 1-3%, methyl acrylate copolymer 1-3%, also containing surfactant 1-3%, thickening agent 0.1-2.5%, antifreeze 3-7%, preservative 0.1-0.3%, defoaming agent 0.2-0.3%, deionized water to 100%; Wherein the block polyether is DS9100 polyurethane polyether E0 / P0 block; The methyl acrylate copolymer is DISPER D1000; The surfactant is phenylethyl phenol polyoxyethylene ether sulfate and phenylethyl phenol phenyl polyoxyethylene polyoxypropylene ether.

2. The suspension concentrate comprising mesotrione according to claim 1, characterized in that: The anhydrous citric acid content is 0.6%.

3. The suspension concentrate comprising mesotrione according to claim 1, characterized in that: The surfactant is phenylethyl phenol polyoxyethylene ether sulfate 1-2%, phenylethyl phenol phenyl polyoxyethylene polyoxypropylene ether 0.2-0.5%.

4. The suspension concentrate comprising mesotrione according to claim 1, characterized in that: The thickening agent is one or more combinations of xanthan gum, magnesium aluminum silicate, gelatin, sodium carboxymethyl cellulose, polyvinyl alcohol, modified starch, hydroxyethyl cellulose, bentonite, silicon dioxide, white carbon black; the antifreeze is one or more combinations of ethylene glycol, glycerol, polyethylene glycol, sorbitol, urea; the preservative is one or more combinations of sodium benzoate, sodium salicylate, propionic acid, sorbic acid; the defoaming agent is silicone defoaming agent.

5. A process for the preparation of the suspension concentrate comprising mesotrione according to claim 1, characterized in that Comprising the following steps: (1) adding a metered amount of water to the stirred tank, starting stirring, adding additives and stirring uniformly, then adding metered amounts of mesotrione, ametryn and cyanazine raw drugs and stirring uniformly; (2) placing the material in the first sand mill for coarse grinding, and storing the coarsely ground material in the first transfer tank; (3) when the material in the first transfer tank has a certain amount, the material is transferred to the second sand mill for fine grinding, and the material fine ground by the second sand mill is stored in the second transfer tank; (4) when the material in the second transfer tank has a certain amount, the material is transferred to the third sand mill for fine grinding, and the material fine ground by the third sand mill is stored in the third transfer tank; (5) after fine grinding to D90≤7μm, the material in the third transfer tank is transferred to the mixing kettle, and stirring is performed until uniform to obtain the finished product.

6. Use of a suspension concentrate comprising mesotrione according to claim 1, characterized in that Preventing and treating crop weeds.

7. Use of a suspension concentrate comprising mesotrione according to claim 6, characterized in that The crop is corn.

8. Use of a suspension concentrate comprising mesotrione according to claim 7, characterized in that The weeds include grass weeds, broadleaf weeds and sedge weeds. The crop is corn.

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