Dzomet suspending agent preparation and preparation method thereof

Abstract

The invention relates to a dazomet suspending agent preparation and a preparation method thereof, and dazomet accounts for 1-75% of the total weight of the preparation. Compared with the prior art, the operation steps of suction filtration, centrifugation, drying and the like in the dazomet raw medicine synthesis process can be omitted, the emission and treatment cost of three wastes is reduced, meanwhile, the application mode of modern facility agriculture is met, and the practical requirements of safety, environmental protection and use are met.

Description

Technical Field

[0001] The invention relates to the technical field of pesticide preparations, and in particular to a dazomethane 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 applications. 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, and achieving the effect of cleaning the soil. However, dazomethane is usually applied in the form of solid particles, and there are problems such as complicated application method, high operation requirements, large dust pollution, and solid particle products are easy to agglomerate, and decomposition is not thorough in practical applications, which is very easy to cause drug damage. Further, factors such as ambient temperature, soil moisture, product particle size, and distribution in soil 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 is an environmentally friendly liquid formulation with the characteristics of dust-free production process, low processing cost, safety and environmental protection, etc. It is easy to measure during use and convenient for precise application through drip irrigation. The physicochemical properties of the active ingredients affect the possibility of its processing into a suspension formulation. Dazomethane has a certain water solubility (solubility <0.3g / 100ml at 20℃), its chemical structure is a non-aromatic six-membered ring, and the carbon-sulfur double bond in the chemical structure may have the possibility of enol interconversion. These factors bring great challenges to the development of its stable suspension.

[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 and applied to the treatment of industrial water. The system has a single type of auxiliary agent and poor dilution stability, which makes it difficult to apply in the agricultural field.

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

[0006] In view of the shortcomings of the prior art, the present invention aims to provide a dazomethon suspension preparation and a preparation method thereof. By screening a specific dispersant, a dazomethon suspension system with stable performance is obtained, and the preparation can be dispersed in water to form a uniform and stable suspension system, which can significantly improve the activity of the effective ingredient dazomethon. The scheme of the present invention can well meet the actual needs of 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 percentage: 1% to 75% dazomethon, 0.1% to 25% auxiliary agent, and the rest is supplemented to 100% by dispersion medium.

[0009] Specifically, the weight percentage of dazomethon in the dazomethon 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 point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the said range.

[0010] Specifically, the weight percentage of the auxiliary agent in the dazomethan 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 point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the said range.

[0011] Preferably, the suspending agent comprises the following components by weight percentage: 10% to 65% dazomet, 0.1% to 20% adjuvant, 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 for preparing pesticide preparations, including one or more of dispersants, wetting agents, thickeners, defoamers, and antifreeze agents; the dispersion medium is selected from 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 referring to the filtrate and washing water generated in the production process of dazomethon dry product, including the filtrate after filtering the dazomethon reaction liquid, and the washing water generated by washing the filter cake.

[0014] Alternatively, the commonly used auxiliary agents 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 additives 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 additives.

[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 methyl naphthalene sulfonate formaldehyde condensate, sodium salt of phenol sulfonic 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, the stabilizer being selected from one or more of 1,2-butanediol, isopropyl phosphate, bentonite, sodium benzoate, linseed oil, hydroquinone, borax, and triethanol 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 suspension of the present invention, the preferred auxiliary agent includes a polycarboxylate dispersant, which is 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 ethylene, propylene, N-vinyl pyrrolidone, styrene, methyl styrene and other monomers 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 accessing other functional groups through carboxyl groups, amino groups, amino groups and sulfhydryl groups. The polycarboxylate dispersant 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. In order to achieve good dispersibility, the dispersant of the polycarboxylate of the present invention usually contains 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 grafted polymers containing these monomers.

[0025] Preferably, the weight average molecular weight of the polycarboxylate dispersant in the present invention is 2000-100000, and the carboxyl content is 5-50%.

[0026] Preferably, the weight average molecular weight of the polycarboxylate dispersant in the present invention is 6000-60000, and the carboxyl content is 10-35%.

[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. The organic salts include ammonium salts, methylamine, triethylamine, triethanolamine, etc., and the 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 components by weight percentage: 1% to 75% dazomet, 0.5% to 25% dispersant, 0.1% to 10% wetting agent, 0.1% to 10% thickener, 0.1% to 10% defoaming agent, 0.1% to 10% antifreeze agent, and the dispersion medium is used to make up to 100%.

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

[0031] Among them, the dispersant, wetting agent, thickener, defoaming agent and antifreeze agent are defined as 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, phenol sulfonic acid condensate sodium salt, sodium lignin sulfonate, dioctyl sulfosuccinic acid 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 dazomethon in the dazomethon suspension of the present invention 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.

[0037] Specifically, the dazomethon raw material in the suspension concentrate of the present invention can be selected from 98% dazomethon microgranules, for example, it can be prepared by referring to the method disclosed in patent application CN107353259A, using methylamine, formaldehyde and carbon disulfide as raw materials, preparing the dazomethon product in an aqueous phase, and if necessary, adding polyamines and / or inorganic salts to improve the granulation performance, and then filtering, drying, sieving and other post-treatment operations to obtain 98% dazomethon microgranules.

[0038] In addition, the dazomethon original drug 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 suspension of the present invention is selected from the untreated dazomethon reaction solution or the filtered dazomethon wet product. The above ingredients can effectively simplify the operation steps, avoid the filtering, drying and screening steps in the preparation process of the solid product, reduce the overall production cost, and have a good environmental protection effect.

[0041] In the suspension of the present invention, the aqueous dispersion medium is selected from one or more of deionized water, ionized water, or 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 of various valence states such as calcium, magnesium, copper, zinc, iron, sodium and potassium, 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 of the present invention is selected from water containing organic matter, specifically filtrate and washing water generated in the production process of dry dazomethon. Since dazomethon technical is dissolved in these wastewaters and often contains a certain amount of dazomethon small particle suspension, using this as the dispersion medium of the suspension agent can improve the comprehensive utilization rate of dazomethon, and can also reduce the discharge of three wastes, which is beneficial to environmental protection.

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

[0045] In a third aspect, the present invention provides a method for preparing a dazomethon suspension preparation, which comprises 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 and stirring, and then adding the remaining thickener to adjust the viscosity.

[0046] In addition, the present invention also provides a method for preparing dazomethon oil suspension, which comprises the following steps: stirring and dispersing dazomethon, an emulsifier, a thickener and a dispersion medium, adding a dispersant, and then sand-milling to obtain the dazomethon 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 prepared suspension concentrate product ranges from 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℃), and its chemical structural formula is a non-aromatic six-membered ring, and the carbon-sulfur double bond in the chemical structure has the possibility of enol interconversion. When the dazomet original drug is processed into a suspension, its preparation is prone to 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 changes, and the preparation formula needs to be optimized to improve stability. On the basis of obtaining a stable suspension, the applicant unexpectedly found that introducing a polycarboxylate adjuvant as a dispersant can better solve the above problems, thereby obtaining a more stable suspension formulation, and 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 points, which can be firmly "anchored" on the surface of pesticide particles, while the side chains are hydrophilic and can be stretched in water, thereby forming a huge three-dimensional adsorption structure on the surface of pesticide particles, effectively producing a steric hindrance effect. When the polymer polycarboxylate dispersant is adsorbed on the interface of pesticide particles, its carboxylic acid group, as a weak negatively charged group, can be well combined with the nitrogen in the dazomethane molecule, so that the pesticide particles are negatively charged, which will form a diffuse double layer around the dispersed particles, thereby generating 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 suspension of pesticide particles can be made more durable.

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

[0051] 1) Excellent environmental protection effect: the existing solid dazomethan easily generates dust during the spreading process, causing harm to the environment, and the wastewater produced by the production of dazomethan requires additional treatment. In contrast, the production process of the dazomethan suspension of the present invention has no dust hazard, and the ungranulated reaction liquid can be directly used or diluted with water when used, which is safer for both the operator and the environment.

[0052] 2) Improved ease of use: The existing solid dazomethane application method is usually to first broadcast and then mechanically till the soil, which is a single method and cumbersome to operate. In contrast, the dazomethane suspension of the present invention can be applied by drip irrigation, flushing, injection, spraying and other methods, and is more flexible and diverse to use. The suspension can be flushed into the soil after being diluted twice with water, without the need for a large rotary tiller, saving time and effort.

[0053] 3) Excellent storage and transportation performance: The existing solid dazomethane is easy to cause particles to compact due to moisture absorption or external force extrusion during storage and transportation. The compacted particles will lead to uneven application of the pesticide, excessive local concentration and difficulty in degradation, which may cause pesticide damage. In contrast, the dazomethane suspension of the present invention can well avoid the above problems and has more stable storage and transportation performance.

[0054] Figures and their descriptions

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

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

[0057] In order to better understand the essence of the present invention, the content of the present invention is further described below in conjunction with the examples, but it cannot be regarded as limiting the present invention. The content mentioned in the examples is not limiting the present invention. The material formula selection can be adapted to local conditions and has no substantial effect on the results. In these examples, unless otherwise specified, all percentages are weight percentages.

[0058] Test Example 1: Dispersant Category Screening

[0059] 1. Test methods

[0060] According to the different properties and functions of the tested dispersants, compliance selection was carried out for different types of dispersant additives such as lignin sulfonate, sulfate ester salt, sulfonate, naphthalene sulfonate, potassium phosphate, polycarboxylate, etc. Appropriate dispersant additives were combined into 9 composite formulas and 6 single-use formulas for screening by repeated test method.

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

[0062] The preparation method of dazomethane suspension is as follows: put the active ingredient of pesticide, dispersant, wetting agent, defoamer, part of thickener and water into a sand mill, grind, cool, filter, add antifreeze and stir, then add the remaining thickener to adjust the viscosity, and the suspension is obtained. The state of the sample is continuously observed during the process. The sample is stored at 54°C for 14 days and then the heat storage stability is measured (refer to GB / T19136-2003 for details).

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

[0064] Table 1 Sand grinding matching classification standard

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

[0066] Table 2 Stability enhancement (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 screening of adjuvants in Table 4, the matching of the formulation of different adjuvants to the dazomethane suspension concentrate was obtained, as shown in Table 5.

[0076] Table 5: Compatibility of different additives with dazomethane 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 better than that of other types of dispersants, which is specifically manifested in that the sand grinding compatibility and formula stability are both +++++, and the 12-month stability is +++; 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, and the sand grinding compatibility and formula stability are both improved to +++++ when the total amount remains unchanged; it can be seen from the comparison of Examples 11 to 14 that the dispersant contains polycarboxylates, the sand grinding compatibility is +++++, and as the amount of polycarboxylates increases, the formula stability gradually improves.

[0079] In summary, it can be seen that when screening dispersants to prepare dazomethane suspension, polycarboxylates are used as dispersants, 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 methods

[0082] According to the different properties and functions of the tested dispersants, the conformity selection was carried out for different monomers and polycarboxylate dispersants. The appropriate dispersant additives were combined into 6 single-use formulas and screened by repeated test methods.

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

[0084] The preparation method of dazomethane suspension is as follows: put the active ingredient of pesticide, dispersant, wetting agent, defoamer, part of thickener and water into a sand mill, grind, cool, filter, add antifreeze and stir, then add the remaining thickener to adjust the viscosity, and the suspension is obtained. The state of the sample is continuously observed during the process. The sample is stored at 54°C for 14 days and then the heat storage stability is measured (refer 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 screening results of polycarboxylates in Table 6, the compatibility of different carboxyl groups and molecular weights with dazomethane 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 dazomethane suspension concentrate

[0091]

[0092] According to the screening of polycarboxylates with different carboxyl contents and molecular weights in Table 7, it can be seen that selecting polycarboxylates with a carboxyl content of 10% to 35% and a molecular weight of 6000 to 60000 as dispersants can significantly improve the formula matching of the dazomethon suspension, which is specifically manifested in the best sand milling matching and formula stability of the dazomethon suspension.

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

[0094] 1. Test methods

[0095] According to the different performance and functions of the tested dispersants, compliance selection was carried out for different dispersion media and sources of Dazomethane technical. Appropriate dispersant additives were combined into 14 formulations and screened by repeated test method.

[0096] Weigh each component according to the following mass percentage (see Table 7 for specific composition and dosage): pesticide active ingredient (dazomethane); dispersant; wetting agent; antifreeze (ethylene glycol) total amount is 3%; defoaming agent (SAG-1522 (Maitu)) total amount is 0.3%; thickener: magnesium aluminum silicate is 0.5%, xanthan gum is 1.0%; the remaining amount is 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 of dazomethane suspension is as follows: put the active ingredient of pesticide, dispersant, wetting agent, defoamer, part of thickener and dispersion medium into a sand mill, grind, cool, filter, add antifreeze and stir, then add the remaining thickener to adjust the viscosity, and the suspension is obtained. The state of the sample is continuously observed during the process. The sample is stored at 54°C for 14 days and then the heat storage stability is measured (refer 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] According to the screening of different specifications of dazomethon raw materials and dispersion media, it can be known that dazomethon raw materials include dazomethon reaction solution (27%), dazomethon wet product (85%), and dazomethon dry product (98%), and the dispersion medium includes deionized water, ionized water, and water containing organic matter, all of which are suitable for the dazomethon suspension system of the present invention. According to the HGT2467.5-2003 pesticide suspension product standard compilation specification, the cases in Table 8 meet the product standards after testing and are qualified products. The main indicators of some embodiments are shown in Table 9:

[0105] Table 9 Main indicators of some examples

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

[0108] Table 10 10% Dazomethane·Quarterly phosphonium salt solution and its composition

[0109]

[0110] According to the details of each component in Table 10, 98% dazomethon microgranules, tetradecyl tributyl phosphonium chloride, cyclohexane, XPO-5 and deionized water were weighed in proportion, mixed and stirred evenly to prepare 10% dazomethon·quaternary phosphonium salt water. It was verified that after the product obtained in Comparative Example 1 was allowed to stand for 2 hours, obvious dazomethon microgranules precipitation was visible at the bottom, and the formula was a non-true solution aqueous preparation, in which the solubility and stability of dazomethon were extremely low.

[0111] Test Example 4: Test on the uniformity and penetration of dazomethane in field soil

[0112] 1. Experimental purpose: To study the horizontal and vertical distribution of liquid dazomethane in the soil layer after application, and the horizontal uniformity of 98% dazomethane microgranules in the soil surface layer after application. The horizontal uniformity of application is compared by multi-point standard deviation.

[0113] 2. Test methods

[0114] 1) Test drug

[0115] Treatment 1: Formulation Example 29;

[0116] Treatment 2: 98% Dazomethane microgranules (particle size range: 40-140 mesh ≥ 85%), manufacturer: Shun Yi Co., Ltd.

[0117] 2) Experimental design

[0118] Average dosage per mu: The dosage of active ingredients in treatments 1 and 2 is 40KG / mu.

[0119] Plot arrangement: Plots are arranged in random blocks. The treatment area is 100m 2 .

[0120] 3) Application method

[0121] Treatment 1 was carried out by flushing: it was directly added to the water tank of each plot and flushed with water, with a water consumption of 45 liters / m2;

[0122] Treatment 2 was carried out by combining 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.

[0123] 4) Test method

[0124] Step 1: Land preparation. Before land preparation, the remaining straw, dead branches, and roots in the plot should be removed. If 98% Dazomethane microgranules are applied, a rotary tiller should be used to plough the soil 40-45 cm deep to loosen the soil and maintain permeability.

[0125] Step 2: Apply the pesticide, refer to the above-mentioned application method.

[0126] Step 3: Take soil samples. Immediately after applying the pesticide, start taking soil samples. Use a soil sampler to take 0 (soil surface), 10, 20, 30,

[0127] The five-point method was used to sample five soil layers at a depth of 40 cm. Five soil samples were taken at each point, each weighing 10 g. A total of 50 g of soil samples were placed in a mortar and ground (to improve the uniformity of soil sampling). Another 2 g of mixed soil sample was taken and placed in a 20 ml centrifuge tube.

[0128] Step 4: Test the content. The retrieved surface soil samples are immediately tested for dazomethane content.

[0129] The method for applying Dazomethane microgranules was referred to [Liu Chunyan et al. Field efficacy test of 98% Dazomethane microgranules for controlling cucumber root-knot nematodes [J]. Beijing Horticulture, 2011, (23)]. The method for detecting the content of Dazomethane in soil was referred to [Feng Yizhi et al. Residue analysis method of Dazomethane and its metabolite methyl isothiocyanate in tomatoes and soil [J]. Pesticides, 2013, 5 (25)].

[0130] 3. Test process

[0131] This experiment was carried out in Xianju, Taizhou. The pesticide was applied on March 21, 2024, and the content of dazomethane in the soil samples was tested on the same day. The highest temperature in the area during the application of pesticides was 24℃ and the lowest temperature was 13℃.

[0132] 4. Test results

[0133] Based on the above conditions, the test results designed by the present invention are shown in Table 11.

[0134] Table 11 Test results

[0135]

[0136] Conclusion: Table 11 shows that the standard deviation of Formulation Example 29 is significantly less than that of 98% Dazomethane microgranules. After application, Formulation Example 29 has a higher consistency rate of distribution of Dazomethane content in the soil surface layer and is more evenly distributed. Formulation Example 29 has good water distribution in the soil and can be distributed with water to the soil layer below 40 cm. Although the soil has a certain adsorption effect on Dazomethane, it can still be distributed with water to the deep soil.

[0137] Test Example 5: Oil Suspension Concentrate Screening

[0138] 1. Test methods

[0139] According to the different properties and functions of the tested dispersants, compliance selection is made for the dispersible oil suspension formulation.

[0140] Weigh the components according to the following mass percentages (see Table 12 for specific composition and dosage): pesticide active ingredient (98% dazomethane dry product); emulsifier; dispersant; thickener; the remaining amount is added to the dispersion medium to make up the total weight of 100 g.

[0141] Table 12 Formulation Examples 36-37 and their compositions

[0142]

[0143] According to the HG / T2467.5-2003 pesticide suspension product standard writing specification, the cases in Table 9 have been tested to meet all product standards and are qualified products.

[0144] 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 dazomethane suspension preparation, characterized in that The suspending agent comprises the following components by weight percentage: 1% to 75% of dazomet, 0.1% to 25% of auxiliary agent, and the rest is supplemented to 100% by dispersion medium.

2. The suspending agent according to claim 1, characterized in that 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.

3. The suspending agent according to any one of claims 1 or 2, characterized in that The auxiliary agent includes one or more of a dispersant, a wetting agent, a thickener, a defoaming agent, and an antifreeze agent; and the dispersion medium is selected from an aqueous dispersion medium.

4. The suspending agent according to any one of claims 1 or 2, characterized in that The auxiliary agent includes one or more of a dispersant, an emulsifier, and a thickener; and the dispersion medium is selected from a non-aqueous dispersion medium.

5. The suspending agent according to any one of claims 1 or 2, characterized in that The auxiliary agent includes a polycarboxylate dispersant.

6. The suspending agent according to any one of claims 1 or 2, characterized in that 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.

7. The suspension according to claim 3, characterized in that The auxiliary agent includes a polycarboxylate dispersant.

8. The suspension concentrate according to claim 3, characterized in that The aqueous dispersion medium is selected from one or more of deionized water, ionized water, and water containing organic matter; the water containing organic matter is selected from the filtrate and washing water generated in the production process of dazomethane dry product.

9. The suspension concentrate according to claim 5, characterized in that The weight average molecular weight of the polycarboxylate dispersant is 2000-100000, and the carboxyl content is 5-50%.

10. The suspension concentrate according to claim 7, characterized in that The weight average molecular weight of the polycarboxylate dispersant is 2000-100000, and the carboxyl content is 5-50%.

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