A dazomethon suspension preparation and its preparation method

Abstract

The present invention relates to a dazomethon suspension preparation and a preparation method thereof, wherein the weight percentage of dazomethon in the preparation is 1% to 75%. Compared with the existing technology, the preparation can eliminate the operation steps such as suction filtration, centrifugation, and drying during the synthesis of dazomethon technical, thereby reducing the emission of "three wastes" and treatment costs. At the same time, it meets the application methods of modern facility agriculture and meets the actual needs of safety, environmental protection, and use.

Description

Technical Field

[0001] The present invention relates to the technical field of pesticide preparations, in particular to a dazomethon suspension preparation and a preparation method thereof. Background Art

[0002] Dazomethane is a kind of environmentally friendly broad-spectrum soil fumigant with high efficiency, low toxicity and no residue, and has a wide range of uses. Dazomethane is decomposed into toxic methyl isothiocyanate, formaldehyde and hydrogen sulfide in the soil, effectively killing various nematodes, pathogens, underground pests and germinated weed seeds in the soil, thereby achieving the effect of cleaning the soil. However, dazomethane is usually applied in the form of solid particles, which has the problems of complicated application method, high operation requirements, large dust pollution, and easy agglomeration of solid particle products. In actual application, decomposition is not thorough, which easily causes drug damage. Further, factors such as ambient temperature, soil moisture, product particle size, distribution in soil, etc. will affect the effect of application, and the ground needs to be covered with film immediately after use, which is easy to produce secondary diseases due to improper application.

[0003] Pesticide suspension concentrates (SCs) are environmentally friendly liquid formulations characterized by dust-free production, low processing costs, safety, and environmental friendliness. They are also easy to meter and facilitate precise application via drip irrigation. However, the physicochemical properties of the active ingredient hinder their potential for processing into SCs. Dazomethane has a moderate water solubility (solubility <0.3g / 100ml at 20°C), a non-aromatic six-membered ring structure, and the presence of a carbon-sulfur double bond in its chemical structure creates the potential for enolic interconversion. These factors pose significant challenges to the development of a stable SC.

[0004] Chinese patent application CN104054748A discloses a bactericide and algaecide suitable for industrial water systems and its application. A composition of dazomethon and tetradecyltributylphosphonium chloride is prepared into an aqueous solution for the treatment of industrial water. However, the system has a single type of auxiliary agent and poor dilution stability, making it difficult to apply in the agricultural field.

[0005] In summary, there is a gap in the research of suspension preparations of dazomet. The invention in this field develops high-performance suspension preparations of dazomet by screening specific dispersants to meet the actual needs in processing, storage, safety, environmental protection and use. Summary of the Invention

[0006] To address the shortcomings of the prior art, the present invention provides a dazomethon suspension concentrate formulation and a method for its preparation. By selecting a specific dispersant, a stable dazomethon suspension concentrate system is obtained. This formulation can be dispersed in water to form a uniform, stable suspension system, significantly enhancing the activity of the active ingredient, dazomethon. The present invention effectively meets practical requirements for processing, storage, safety, environmental protection, and use.

[0007] To achieve this object, the present invention adopts the following technical solutions:

[0008] In a first aspect, the present invention provides a dazomethon suspension preparation, which comprises the following components by weight: 1% to 75% dazomethon, 0.1% to 25% adjuvant, and the remainder is supplemented to 100% by dispersion medium.

[0009] Specifically, the weight percentage of dazomet in the dazomet suspension is 1% to 75%, for example, it can be 2%, 4%, 8%, 10%, 12%, 15%, 18%, 20%, 24%, 28%, 30%, 35%, 38%, 40%, 42%, 45%, 47%, 50%, 52%, 55%, 58%, 60%, 63%, 65%, 68%, 70%, 72% or 74%, as well as specific values ​​between the above points. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific points included in the said range.

[0010] Specifically, the weight percentage of the adjuvant in the dazomethon suspension is 0.1% to 25%, for example, it can be 0.2%, 0.5%, 1%, 2%, 3%, 4%, 5%, 7%, 9%, 10%, 12%, 15%, 18%, 20%, 22% or 24%, as well as specific values ​​between the above points. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific points included in the said range.

[0011] Preferably, the suspending agent comprises the following components by weight percentage: 10% to 65% of dazomet, 0.1% to 20% of auxiliary agent, and the rest is supplemented to 100% by dispersion medium.

[0012] In the suspension concentrate of the present invention, the adjuvants used are conventional adjuvants and auxiliary ingredients required for the preparation of pesticide formulations, including one or more of a dispersant, a wetting agent, a thickener, a defoaming agent, and an antifreeze agent; the dispersion medium is selected from an aqueous dispersion medium;

[0013] As an embodiment of the present invention, the aqueous dispersion medium is selected from one or more of deionized water, ionized water, and water containing organic matter; in the present invention, the water containing organic matter is selected from the wastewater generated in the preparation process of dazomethon, specifically the filtrate and washing water generated in the production process of dry dazomethon, including the filtrate after filtering the dazomethon reaction liquid and the washing water generated by washing the filter cake.

[0014] Alternatively, the commonly used adjuvants of the present invention include one or more of dispersants, emulsifiers, and thickeners; and the dispersion medium is selected from non-aqueous dispersion medium, selected from one or more of vegetable oils, chemically modified vegetable oils, and mineral oils.

[0015] In the field of agrochemicals, dispersants and wetting agents are distinguished by their application performance. However, some adjuvants have both dispersing and wetting functions and can also be called dispersing and wetting agents, such as EO / PO block polyethers, naphthalene sulfonates and other adjuvants.

[0016] Specifically, the dispersant is selected from one or more of polycarboxylates, polyoxyethylene ether phosphates, EO / PO block polyethers, condensed naphthalene sulfonates, sodium methylene dinaphthalene sulfonate, sodium methylnaphthalene sulfonate formaldehyde condensate, sodium salt of phenolsulfonic acid condensate, sodium lignin sulfonate, sodium salt of dioctyl sulfosuccinate, and alkyl sulfate ester salts;

[0017] Specifically, the wetting agent is selected from one or more of EO / PO block polyether, fatty alcohol polyoxyethylene ether, fatty alcohol ethoxylate, tallow ethoxylate ammonium salt, alkyl naphthalene sulfonate, fatty alcohol polyoxyethylene ether sulfate, condensed naphthalene sulfonate, and acyl glutamate;

[0018] Specifically, the thickener is selected from one or more of xanthan gum, carboxymethyl cellulose, gelatin, gum arabic, polyvinyl pyrrolidone, carboxyethyl cellulose, methyl cellulose, magnesium aluminum silicate and polyvinyl alcohol;

[0019] Specifically, the defoaming agent is selected from one or more of sucrose fatty acid esters, silicones, fatty acids, mineral oils, and alcohols;

[0020] Specifically, the antifreeze agent is selected from one or more of ethylene glycol, glycerol, propylene glycol, polyethylene glycol, sorbitol or urea.

[0021] Furthermore, the preparation of the present invention may also be added with an appropriate amount of a stabilizer, which is selected from one or more of 1,2-butanediol, isopropyl phosphate, bentonite, sodium benzoate, linseed oil, hydroquinone, borax, and triethanolol oleate.

[0022] The application of the above-mentioned auxiliary materials is to achieve the stability of the physical properties of the dosage form and achieve the field application effect. The types, functions, and application techniques of the auxiliary materials are referred to Zhang Xiaojun, Liu Guangwen, et al. [Pesticide Adjuvants, (2018, Chemical Industry Press)].

[0023] In the suspending agent of the present invention, preferred auxiliary agents include polycarboxylate dispersants, which are mainly obtained by polymerization of unsaturated monomers containing carboxyl groups, such as acrylic acid, maleic acid, methacrylic acid, etc. or their corresponding esters and amides; in the polymerization, other unsaturated monomers containing carbonyl groups, such as monomers such as ethylene, propylene, N-vinyl pyrrolidone, styrene, and methyl styrene, can be added for functional needs; in addition, various functional groups, such as various heterocycles, sulfonic acid groups, sulfonyl groups, etc., can be introduced by various chemical methods; further grafting modification can also be performed, such as by accessing other functional groups such as carboxyl groups, amino groups, amino groups and sulfhydryl groups. The polycarboxylate dispersants of the present invention can also contain amino groups, amino groups and sulfhydryl groups in polymer compounds, and carboxylic acid groups, or their corresponding esters and amides, are grafted into them. In order to achieve good dispersibility, the dispersants of the polycarboxylates of the present invention usually include polar groups and non-polar groups.

[0024] As an embodiment of the present invention, the monomers of the polycarboxylate dispersant of the present invention include monomers containing sodium salt of maleic anhydride copolymer, monomers containing sodium salt of maleic anhydride acrylic acid copolymer, monomers containing styrene sulfonate polymer, monomers containing polyacrylate and graft polymers containing these monomers.

[0025] Preferably, the weight average molecular weight of the polycarboxylate dispersant in the present invention is 2,000 to 100,000, and the carboxyl content is 5 to 50%.

[0026] Preferably, the weight average molecular weight of the polycarboxylate dispersant in the present invention is 6,000 to 60,000, and the carboxyl content is 10 to 35%.

[0027] Specifically, the present invention uses polycarboxylate dispersants available in agricultural chemicals, such as TERSPERSE 2735, T36, Agrilan 700, GY-D series, SP-27001, Dispersogen C 4020, and the like.

[0028] In addition, the polycarboxylate dispersants in the present invention include organic salts and / or inorganic salts thereof. Organic salts include ammonium salts, methylamine, triethylamine, triethanolamine, etc., and inorganic salts include potassium salts, sodium salts, calcium salts and zinc salts, etc.

[0029] As an embodiment of the present invention, the suspending agent includes the following ingredients, calculated by weight percentage: 1% to 75% of dazomet, 0.5% to 25% of dispersant, 0.1% to 10% of wetting agent, 0.1% to 10% of thickener, 0.1% to 10% of defoaming agent, and 0.1% to 10% of antifreeze, and the dispersion medium is used to make up to 100%.

[0030] Furthermore, as a preferred embodiment of the present invention, the suspending agent comprises the following ingredients by weight percentage: 10% to 65% of dazomet, 0.5% to 20% of dispersant, 0.5% to 8% of wetting agent, 0.1% to 5% of thickener, 0.1% to 5% of defoaming agent, 0.1% to 5% of antifreeze agent, and the dispersion medium is used to make up to 100%.

[0031] The definitions of dispersants, wetting agents, thickeners, defoaming agents and antifreeze agents are as described above.

[0032] Furthermore, the dispersant is a polycarboxylate dispersant, or a combination of different types of polycarboxylate dispersants, or a combination of a polycarboxylate dispersant and other types of dispersants, and the other types of dispersants are selected from one or more of polyoxyethylene ether phosphate, EO / PO block polyether, condensed naphthalene sulfonate, sodium methylene dinaphthalene sulfonate, sodium methyl naphthalene sulfonate formaldehyde condensate, phenolsulfonic acid condensate sodium salt, sodium lignin sulfonate, dioctyl sulfosuccinate sodium salt, and alkyl sulfate ester salts.

[0033] As an embodiment of the present invention, based on the total weight percentage, the polycarboxylate dispersant in the dispersant is 0.5% to 15%, and the other dispersants in the dispersant are 0% to 10%.

[0034] As a preferred embodiment of the present invention, based on the total weight percentage, the polycarboxylate dispersant in the dispersant is 0.5% to 12%, and the other dispersants in the dispersant are 0% to 8%.

[0035] Preferably, the monomers of the polycarboxylate dispersant are monomers containing sodium salt of maleic anhydride acrylic acid copolymer, monomers containing maleic acid copolymer, and monomers containing styrene sulfonate polymer; the weight average molecular weight of the polycarboxylate dispersant is 2000-100000, and the carboxyl content is 5-50%. Preferably, the weight average molecular weight is 6000-60000, and the carboxyl content is 12-35%.

[0036] Furthermore, the active ingredient dazomet in the dazomet suspension of the present invention is selected from one or more of 98% dazomet microgranules, untreated dazomet reaction solution, reaction solution before solid filtration, wet product obtained after filtration, or dry product obtained after drying.

[0037] Specifically, the dazomethon technical in the suspension concentrate of the present invention can be selected from 98% dazomethon microgranules, which can be prepared, for example, by the method disclosed in patent application CN107353259A, using methylamine, formaldehyde, and carbon disulfide as raw materials to prepare a dazomethon product in an aqueous phase. If necessary, polyamines and / or inorganic salts can be added to improve granulation performance, and then the 98% dazomethon microgranules are obtained through post-processing operations such as filtration, drying, and sieving.

[0038] In addition, the dazomethon technical in the suspension concentrate of the present invention can also be selected from the dazomethon reaction solution without post-treatment, the reaction solution before solid filtration, the wet product obtained after filtration or the dry product obtained after drying, or any combination of the above products.

[0039] Among them, the unpost-treated dazomethon reaction liquid is the reaction liquid obtained after the reaction of the raw materials in the synthesis is completed but not dehydrated; the dazomethon wet product is the product obtained by filtering the dazomethon reaction liquid but not drying it; and the dazomethon dry product is the product obtained after drying the dazomethon wet product.

[0040] Preferably, the active ingredient in the suspending concentrate of the present invention is selected from an untreated dazomethon reaction solution or a filtered dazomethon wet product. Using such an ingredient effectively simplifies the process, avoids the filtration, drying, and screening steps required in the solid product preparation process, reduces overall production costs, and offers excellent environmental benefits.

[0041] In the suspension of the present invention, the aqueous dispersion medium is selected from one or more of deionized water, ionized water, and water containing organic matter.

[0042] Specifically, deionized water refers to pure water from which impurities in the form of ions have been removed; ionized water refers to an aqueous solution containing inorganic substances, such as anions such as chloride ions, sulfate ions and nitrate ions, and an aqueous solution containing cations such as calcium, magnesium, copper, zinc, iron, sodium and potassium in various valence states, and can also be a combination of multiple ions; water containing organic substances refers to an aqueous solution containing water-soluble organic substances, such as organic acids, organic amines, alcohols and other water-soluble organic substances, and can also be a mixture of multiple water-soluble substances.

[0043] Preferably, the dispersion medium described herein is selected from water containing organic matter, specifically filtrate and wash water generated during the production of dry dazomethon. Because these wastewaters contain dissolved dazomethon technical and often contain a certain amount of suspended small particles of dazomethon, using them as the dispersion medium for the suspending agent can improve the comprehensive utilization rate of dazomethon while also reducing the discharge of three wastes, thus benefiting the environment.

[0044] In a second aspect, the present invention provides use of a polycarboxylate dispersant in the preparation of a dazomethon suspension concentrate, wherein the weight percentage of the polycarboxylate dispersant in the dazomethon suspension concentrate is 0.5% to 12%, and the remaining definitions are as described above.

[0045] In a third aspect, the present invention provides a method for preparing a dazomethon suspension preparation, comprising the following steps: adding dazomethon, a dispersant, a wetting agent, a defoaming agent, a portion of a thickener, and a dispersion medium into a sand mill, grinding, cooling, adding an antifreeze agent, stirring, and then adding the remaining thickener to adjust the viscosity.

[0046] In addition, the present invention also provides a preparation method of dazomet oil suspension, which comprises the following steps: stirring and dispersing dazomet, an emulsifier, a thickener and a dispersion medium, adding a dispersant, and then sand-milling to obtain the dazomet oil suspension.

[0047] The suspension concentrate described in the present invention is usually prepared by a sand milling process, and the particle size of the suspension concentrate product prepared is in the range of nanometers to micrometers. The general preparation method, process and materials can be found in Ren Tianrui, Dai Quan et al. [Pesticide Formulation and Processing, (2019, Chemical Industry Press)].

[0048] In the prior art, dazomet has a certain water solubility (solubility <0.3g / 100ml at 20°C), and its chemical structure is a non-aromatic six-membered ring. In addition, the carbon-sulfur double bond present in the chemical structure may undergo enol interconversion. When the dazomet original drug is processed into a suspension concentrate, the preparation is prone to problems such as thickening, solidification, or crystallization during hot storage. After a long period of research, the present invention found that the problem of unstable preparation is that the dazomet original drug has a certain solubility in water, and the solubility changes accordingly with temperature, and it is necessary to optimize the preparation formula to improve stability. On the basis of obtaining a stable suspension concentrate, the applicant unexpectedly found that introducing a polycarboxylate adjuvant as a dispersant can better solve the above problems, thereby obtaining a more stable suspension concentrate formula. In particular, when a high molecular weight polycarboxylate dispersant is used, a better effect can be obtained.

[0049] The present invention has been found through in-depth research that the polymer chain in the structure of polycarboxylate dispersants includes a main chain and a plurality of side chains, wherein the main chain has a plurality of active adsorption sites and can be firmly "anchored" on the surface of the pesticide particles, while the side chains are hydrophilic and can stretch in water, thereby forming a large three-dimensional adsorption structure on the surface of the pesticide particles, effectively producing a steric hindrance effect. When the polymer polycarboxylate dispersant is adsorbed on the interface of the pesticide particles, its carboxylic acid group, as a weak negatively charged group, can be well combined with the nitrogen in the dazomethan molecule, so that the pesticide particles are negatively charged, which will form a diffuse double layer around the dispersed particles and generate a Zeta potential. When two dispersed phase ions with the same charge approach each other, the electrostatic repulsion generated by the overlap of the diffuse double layer will force the charged dispersed phase ions to separate from each other, effectively preventing them from merging. Through the mechanism of action of polycarboxylates, especially polymer polycarboxylates, the formulation system can be made more stable and the pesticide particle suspension more durable.

[0050] Compared with the solid dazomet product of the prior art, the advantages of the present invention are:

[0051] 1) Excellent environmental protection effect: Existing solid dazomet easily generates dust during the spreading process, causing harm to the environment, and the wastewater from the production of dazomet requires additional treatment. In contrast, the production process of the dazomet suspension of the present invention does not cause dust hazards. When used, the ungranulated reaction liquid can be directly used or diluted with water, which is safer for both operators and the environment.

[0052] 2) Improved ease of use: Existing solid dazomethane applications typically involve broadcast application followed by mechanical tillage, a single, cumbersome method. In contrast, the dazomethane suspension concentrate of the present invention can be applied via a variety of methods, including drip irrigation, flushing, injection, and spraying, offering greater flexibility and versatility. The suspension concentrate can be diluted twice with water and then flushed into the soil, eliminating the need for a large rotary tiller and saving time and effort.

[0053] 3) Superior storage and transportation performance: Existing solid dazomethon easily compacts during storage and transportation due to moisture absorption or external compression. Compacted particles can lead to uneven application, high local concentrations, and difficulty in degradation, which can cause pesticide damage. In contrast, the dazomethon suspension concentrate of the present invention effectively avoids these problems and offers more stable storage and transportation performance.

[0054] Figures and their descriptions

[0055] Figure 1 The static appearance of some samples in Examples 1-3 is shown in FIG.

[0056] Figure 2 The inverted appearance of some samples in Examples 1-3 is shown. DETAILED DESCRIPTION

[0057] In order to better understand the essence of the present invention, the following examples further illustrate the present invention, but they should not be construed as limiting the present invention. The contents mentioned in the examples are not limitations of the present invention, and the selection of material formulations can be adapted to local conditions without having a substantial impact on the results. In these examples, unless otherwise stated, all percentages are weight percentages.

[0058] Test Example 1: Dispersant Category Screening

[0059] 1. Test method

[0060] Based on the different properties and functions of the tested dispersants, compliance selection was conducted for different categories of dispersant additives, including lignin sulfonates, sulfates, sulfonates, naphthalene sulfonates, potassium phosphates, and polycarboxylates. Appropriate dispersant additives were combined into nine composite formulations and six single-use formulations for screening using a repeated testing method.

[0061] The components were weighed according to the following mass percentages: 20% pesticide active ingredient (98% dazomet dry product); 3-4% dispersant (dispersant composition and dosage are shown in Table 3); 1% wetting agent (EO / PO block polyether or naphthalenesulfonate polycondensate); 3% antifreeze (ethylene glycol); 0.3% defoamer (SAG-1522 (Maitu)); 0.5% thickener: magnesium aluminum silicate, 1.0% xanthan gum; and the remaining amount was made up with tap water, for a total weight of 100 g.

[0062] The preparation method for dazomet suspension concentrate is as follows: Place the pesticide active ingredient, dispersant, wetting agent, defoamer, part of the thickener, and water in a sand mill, grind, cool, filter, add antifreeze, stir, and then add the remaining thickener to adjust the viscosity. The sample's condition is continuously observed during the process. The sample is then stored at 54°C for 14 days and then subjected to a heat storage stability test (referring to GB / T19136-2003 for details).

[0063] The specific evaluation criteria are shown in Table 1, Table 2, and Table 3.

[0064] Table 1 Sanding matching grading standards

[0065] series Grading standards + Sanding failed ++ Can be sanded, but filtration is unsuccessful +++ Filterable, viscous ++++ Fluidity and high viscosity +++++ Good fluidity and low viscosity

[0066] Table 2 Stability Improvement (Dispersant) Classification Standard (54°C)

[0067] series Grading standards + Thermal storage conditions not met ++ Thickening by standing at room temperature +++ Thermal storage curing (0-7 days) ++++ Thermal storage curing (7-14 days) +++++ Hot storage uncured (14 days)

[0068] Table 3 12-month stability standards (30°C)

[0069]

[0070]

[0071] 2. Test results

[0072] The test results are shown in Tables 4 and 5.

[0073] Table 4 Formulation Examples 1-15 and Sample Test Results

[0074]

[0075] According to the adjuvant screening results in Table 4, the compatibility of adjuvants with different ingredients for the formulation of dazomethon suspension concentrate was obtained, as shown in Table 5.

[0076] Table 5: Compatibility of different adjuvant ingredients with the formulation of dazomethan suspension concentrate

[0077]

[0078] As shown in Table 4 and Table 5, it can be seen from the comparison of Examples 1 to 6 that the compatibility of the dispersant polycarboxylate formula with the dazomethon product is far superior to that of other types of dispersants, specifically in that the sand mill compatibility and formula stability are both +++++, and the 12-month stability is all +++; it can be seen from the comparison of Examples 7 to 10 that the dispersant polycarboxylate can be further compounded with other types of dispersants to improve the performance of the suspending agent. When the total amount remains unchanged, the sand mill compatibility and formula stability are both improved to +++++; it can be seen from the comparison of Examples 11 to 14 that the presence of polycarboxylate in the dispersant results in a sand mill compatibility of +++++, and as the amount of polycarboxylate increases, the formula stability gradually improves.

[0079] In summary, it can be seen that when screening dispersants to prepare dazomet suspension concentrate, polycarboxylate is used as the dispersant, and the formula matching is the best, which is specifically manifested in good sand mill matching and significantly improved stability.

[0080] Test Example 2: Screening of dispersant polycarboxylate monomers

[0081] 1. Test method

[0082] Based on the different properties and functions of the tested dispersants, the conformity of different monomers and polycarboxylate dispersants was selected. Appropriate dispersant additives were combined into 6 single-use formulations and screened using the repeated test method.

[0083] The components were weighed according to the following mass percentages: the pesticide active ingredient (98% dry dazomethan) content was 20%; the total amount of dispersant (the composition and amount of the dispersant are shown in Table 5) was 3%; the total amount of wetting agent was 1% (EO / PO block polyether); the total amount of antifreeze (ethylene glycol) was 3%; the total amount of defoaming agent (SAG-1522 (Maitu)) was 0.3%; the thickener: magnesium aluminum silicate was 0.5%, and the xanthan gum was 1.0%; the remaining amount was supplemented with tap water, and the total weight was 100 g.

[0084] The preparation method for dazomet suspension concentrate is as follows: Place the pesticide active ingredient, dispersant, wetting agent, defoamer, part of the thickener, and water in a sand mill, grind, cool, filter, add antifreeze, stir, and then add the remaining thickener to adjust the viscosity. The sample's condition is continuously observed during the process. The sample is then stored at 54°C for 14 days and then subjected to a heat storage stability test (referring to GB / T19136-2003 for details).

[0085] 2. Test results

[0086] The test results are shown in Tables 6 and 7.

[0087] Table 6 Formulation Examples 16-21 and Test Results

[0088]

[0089] According to the polycarboxylate screening results in Table 6, the compatibility of different carboxyl groups and molecular weights with dazomet suspension concentrate was obtained, as shown in Table 7.

[0090] Table 7 Compatibility of polycarboxylates with different carboxyl content and molecular weight with the formulation of dazomet suspension concentrate

[0091]

[0092] According to the screening results of polycarboxylates with different carboxyl content and molecular weight in Table 7, the selection of polycarboxylates with a carboxyl content of 10% to 35% and a molecular weight of 6,000 to 60,000 as dispersants significantly improves the formulation compatibility of dazomet suspension concentrate, which is specifically manifested in the best sand milling compatibility and formulation stability of dazomet suspension concentrate.

[0093] Test Example 3: Dispersant and Dispersion Medium Screening

[0094] 1. Test method

[0095] Based on the different properties and functions of the tested dispersants, compliance was selected for different dispersion media and Dazomethane technical sources. Appropriate dispersant adjuvants were combined into 14 formulations and screened using a repeated testing method.

[0096] The components were weighed according to the following mass percentages (see Table 7 for specific composition and amount): pesticide active ingredient (dazomethon); dispersant; wetting agent; antifreeze (ethylene glycol) totaling 3%; defoaming agent (SAG-1522 (Maitu)) totaling 0.3%; thickener: magnesium aluminum silicate 0.5%, xanthan gum 1.0%; the remaining amount was added to the dispersion medium to make up the total weight of 100 g.

[0097] Among them, the material specifications are selected as follows: dazomethon reaction solution, effective content 27%; dazomethon wet product, effective content 85%; dazomethon dry product, effective content 98%; water containing organic matter refers to the filtrate and washing water generated in the production process of dazomethon dry product; ionized water ①5% calcium chloride aqueous solution, ionized water ②3% sodium sulfate aqueous solution.

[0098] The preparation method for dazomet suspension concentrate is as follows: Place the pesticide active ingredient, dispersant, wetting agent, defoamer, part of the thickener, and dispersion medium in a sand mill, grind, cool, filter, add antifreeze, stir, and then add the remaining thickener to adjust the viscosity. The sample's condition is continuously observed during the process. The sample is then stored at 54°C for 14 days and then subjected to a heat storage stability test (referring to GB / T19136-2003 for details).

[0099] 2. Test results

[0100] The test results are shown in Table 8.

[0101] Table 8 Formulation Examples 22-35 and their compositions

[0102]

[0103]

[0104] Based on the screening of different specifications of dazomethon technical and dispersion media, it can be seen that dazomethon technical includes dazomethon reaction solution (27%), dazomethon wet product (85%), and dazomethon dry product (98%), and dispersion media include deionized water, ionized water, and water containing organic matter, all of which are suitable for the dazomethon suspension concentrate system of the present invention. According to the HGT2467.5-2003 pesticide suspension concentrate product standard compilation specification, the cases in Table 8 were tested and met all product standards and are qualified products. The main indicators of some examples are shown in Table 9:

[0105] Table 9 Main indicators of some examples

[0106] Comparative Example 1: 10% dazomethane-quaternary phosphonium saline solution (refer to the embodiment of Chinese patent application CN104054748A), the specific composition is shown in Table 10.

[0107] Table 10 10% Dazomethane-quaternary phosphonium saline solution and its composition

[0108]

[0109] According to the components detailed in Table 10, 98% dazometon microgranules, tetradecyltributylphosphonium chloride, cyclohexane, XPO-5, and deionized water were weighed in proportion, mixed, and stirred to prepare a 10% dazometon·quaternary phosphonium saline solution. It was verified that after the product obtained in Comparative Example 1 was allowed to stand for 2 hours, a clear precipitate of dazometon microgranules was observed at the bottom, indicating that this formulation was not a true aqueous solution, and the solubility and stability of dazometon were extremely low.

[0110] Test Example 4: Test on the uniformity and penetration of dazomet in field soil

[0111] 1. Experimental Purpose: To study the lateral and longitudinal distribution of liquid dazomet in the soil layer after application, and the lateral uniformity of 98% dazomet microgranules in the soil surface layer after application. Horizontal uniformity was compared using multi-point standard deviation.

[0112] 2. Test methods

[0113] 1) Test drug

[0114] Treatment 1: Formulation Example 29;

[0115] Treatment 2: 98% dazomet microgranules (particle size range: 40-140 mesh ≥ 85%), manufacturer: Shun Yi Co., Ltd.

[0116] 2) Experimental design

[0117] Average dosage per mu: The effective ingredient dosage per mu for treatments 1 and 2 is 40KG / mu.

[0118] Plot arrangement: Plots are arranged in random blocks. The treatment area is 100m 2 .

[0119] 3) Application method

[0120] Treatment 1 was carried out by flushing: the fertilizer was directly added to the water tank of each plot and flushed with water, with a water volume of 45 liters / m2;

[0121] Treatment 2 was carried out by broadcasting and rotary tillage: the dosage was broadcast on the soil surface of the plot and then tilled with a rotary tiller to a depth of 40-45 cm.

[0122] 4) Test method

[0123] Step 1: Land preparation. Before land preparation, remove any remaining straw, dead branches, and roots. If broadcasting 98% Dazomethane Microgranules, use a rotary tiller to plow the soil to a depth of 40-45 cm to loosen and maintain permeability.

[0124] Step 2: Apply the pesticide, refer to the above-mentioned application method.

[0125] Step 3: Take soil samples. Immediately after applying the pesticide, start taking soil samples. Use a soil sampler to take samples at 0 (soil surface), 10, 20, 30,

[0126] Sampling was performed at five depths of 40 cm using the five-point method. Five soil samples, each weighing 10 g, were collected from each point. A total of 50 g of soil was ground in a mortar and pestle (to improve soil sampling uniformity). A 2 g sample of the mixed soil was then placed in a 20 ml centrifuge tube.

[0127] Step 4: Testing the content. The retrieved surface soil samples are immediately tested for dazomet content.

[0128] The application method of Dazomethane microgranules was referred to [Liu Chunyan et al. Field efficacy test of 98% Dazomethane microgranules against cucumber root-knot nematodes [J]. Beijing Horticulture, 2011, (23)]. The detection method of Dazomethane content in soil was referred to [Feng Yizhi et al. Residue analysis of Dazomethane and its metabolite methyl isothiocyanate in tomatoes and soil [J]. Pesticides, 2013, 5 (25)].

[0129] 3. Test process

[0130] This experiment was conducted in Xianju, Taizhou. The pesticide was applied on March 21, 2024, and soil samples were tested for dazomet content on the same day. The highest temperature in the area at the time of application was 24°C, and the lowest was 13°C.

[0131] 4. Test results

[0132] Based on the above conditions, the test results of the present invention are shown in Table 11.

[0133] Table 11 Test results

[0134]

[0135] Conclusion: Table 11 shows that the standard deviation of Formulation Example 29 was significantly less than that of 98% dazomet microgranules. After application, Formulation Example 29 had a higher consistency and more uniform distribution of dazomet in the soil surface. Furthermore, Formulation Example 29 exhibited good water-distribution in the soil, distributing with water to the soil layer below 40 cm. Although soil has a certain adsorption effect on dazomet, it can still be distributed with water to deeper soil layers.

[0136] Test Example 5: Oil Suspension Concentrate Screening

[0137] 1. Test method

[0138] According to the different properties and functions of the tested dispersants, the conformity selection is carried out for the dispersible oil suspension concentrate formula.

[0139] The components were weighed according to the following mass percentages (see Table 12 for specific composition and amount): pesticide active ingredient (98% dazomet dry product); emulsifier; dispersant; thickener; the remaining amount was added to the dispersion medium to make up the total weight of 100 g.

[0140] Table 12 Formulation Examples 36-37 and their compositions

[0141]

[0142] According to the HG / T2467.5-2003 pesticide suspension product standard compilation specification, the cases in Table 9 have been tested and meet all product standards and are qualified products.

[0143] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A dazomethon suspension preparation, characterized in that The suspending agent comprises the following components by weight percentage: 10% to 65% of dazomet, 0.5% to 8% of dispersant, 0.1% to 10% of wetting agent, 0.1% to 10% of thickener, 0.1% to 10% of defoaming agent, 0.1% to 10% of antifreeze agent, and the remainder is supplemented to 100% by dispersion medium. The dispersant is a polycarboxylate dispersant, and the monomer of the polycarboxylate dispersant is a monomer containing sodium salt of maleic anhydride acrylic acid copolymer, a monomer containing maleic acid copolymer, or a monomer containing styrene sulfonate polymer. The weight average molecular weight of the polycarboxylate dispersant is 6,000 to 60,000, and the carboxyl content is 10% to 35%. The dispersion medium is selected from an aqueous dispersion medium.

2. The suspending agent according to claim 1, wherein The active ingredient dazomethon in the dazomethon suspension is selected from one or more of 98% dazomethon microgranules, dazomethon reaction solution without post-treatment, reaction solution before solid filtration, wet product obtained after filtration, or dry product obtained after drying.

3. The suspending agent according to claim 1, characterized in that The aqueous dispersion medium is selected from one or more of deionized water and ionized water.

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