Thiamethoxam water dispersible granules and production process thereof

Abstract

The present invention provides a thiamethoxam water dispersible granule, which comprises thiamethoxam 25%, dispersant 1-6%, wetting agent 1-8%, disintegrant 1-10%, and filler supplemented to 100% by mass percentage. The present invention uses specific dispersant, disintegrant and other auxiliary ingredients, and the obtained thiamethoxam 25% water dispersible granule has excellent and lasting suspension stability and dispersibility, and the suspension performance reaches more than 92.5%, and can be effectively stored, and it is not easy to agglomerate and precipitate after long-term storage; it disintegrates quickly and delicately in aqueous solution, and can disintegrate completely without the presence of dead particles. The thiamethoxam 25% water dispersible granule of the present invention has excellent insecticidal effect when used, and the prevention effect can reach more than 90% 5d after the drug is applied, and can effectively prevent and control various aphids, leafhoppers, planthoppers, whiteflies, beetle larvae, potato beetles, nematodes, ground beetles, leaf miners and other pests and pests that produce resistance to various types of chemical pesticides.

Description

Technical Field

[0001] The invention relates to the technical field of pesticides, and in particular to thiamethoxam water dispersible granules and a production process thereof. Background Art

[0002] Thiamethoxam is a neonicotinoid insecticide developed by Novartis in 1991. Its mechanism of action is similar to that of imidacloprid. It can selectively inhibit the nicotinic acid acetylcholinesterase receptors in the insect central nervous system, thereby blocking the normal conduction of the insect central nervous system, causing paralysis and death of the pests. It belongs to the second generation of neonicotinoid insecticides. Thiamethoxam not only has contact, stomach poison and systemic activity, but also has higher activity, better safety, wider insecticide spectrum, fast action speed and long lasting effect. It is a better variety to replace those organophosphorus, carbamate and organochlorine insecticides that are highly toxic to mammals, have residues and environmental problems. It has high activity against Coleoptera, Diptera, Lepidoptera, especially Homoptera pests, and can effectively control various aphids, leafhoppers, planthoppers, whiteflies, beetle larvae, potato beetles, nematodes, ground beetles, leaf miners and other pests and pests that have developed resistance to various types of chemical pesticides. There is no cross-resistance with imidacloprid, acetamiprid and nitenpyram.

[0003] In the prior art, pesticide active ingredients are often made into various dosage forms for easy use. Water dispersible granules are safe for operators and do not float because they do not contain solvents and dust. They avoid the shortcomings of traditional dosage forms such as emulsifiable concentrates, dust and wettable powders, such as large amounts of solvents and high dust. They absorb and utilize their advantages and develop rapidly. They are considered to be one of the most promising dosage forms in the field of pesticide processing in the 21st century.

[0004] Chinese patent CN107372572A discloses 25% thiamethoxam water dispersible granules, including: thiamethoxam: 25%; dispersant KZ-009: 6.2-6.4%; wetting agent KZ-016: 2-4%; lignin naphthalenesulfonate dispersant KZ-021: 5.8-7.2%; biological protein KZ-088: 71.3-74.6%; stabilizer KZ-031: 1-3%; lactose: 1.5-3%; corn starch: 3-6%; by adding 71.3-74.6% biological protein KZ-088, KZ-088 is used to recreate the production environment of thiamethoxam, so that the biological pesticide avermectin can be more stable under the new formula, so that the various technical indicators of the product are higher, more conducive to the exertion of drug efficacy, more stable to light, safer for the environment, more environmentally friendly, and more efficient. However, there are problems such as incomplete disintegration, inability to maintain stable suspension, and long-term stratification when it is used.

[0005] The wettable powder of the existing thiamethoxam formulation has the problem of dust pollution, and the suspension still has the problem of being difficult to pour and stratification after long-term storage. In the same formulation, the use of different dispersants, disintegrants, and wetting agents will significantly affect the instability of the preparation, and the particles will not disintegrate or disintegrate slowly, and the suspension rate is low. Therefore, the development of a thiamethoxam water-dispersible granule that can quickly and completely disintegrate, has excellent dispersibility and suspension, and has a good insecticidal effect is still a technical problem that needs to be solved urgently. Summary of the invention

[0006] In view of the above problems, the present invention provides a thiamethoxam water dispersible granule, which has excellent and lasting suspension stability, good dispersibility, high suspension rate, fast and fine disintegration; and has excellent insecticidal effect when used.

[0007] On one hand, the present invention provides a thiamethoxam water dispersible granule, which comprises 25% thiamethoxam, 1-6% dispersant, 1-8% wetting agent, 1-10% disintegrant, and filler supplemented to 100% by mass percentage.

[0008] Preferably, the dispersant is a mixture of one or more of naphthalene sulfonate, lignin sulfonate, naphthalene sulfonate formaldehyde condensate, alkylphenol polyoxyethylene ether, phenethylphenol polyoxyethylene ether, succinic acid sulfonate, polycarboxylate, fatty alcohol polyoxyethylene ether, and alkylbenzene sulfonate.

[0009] In order to further improve the suspension rate and dispersibility, it is further preferred that the dispersant is a polycarboxylate dispersant.

[0010] More preferably, the polycarboxylate dispersant is polycarboxylate dispersant SD-819.

[0011] Further preferably, the mass percentage of the dispersant is 3-5%.

[0012] The active ingredient particles of pesticides are easy to aggregate and sink due to their high surface energy. The inventors found that when the polycarboxylate dispersant SD-819 is used, it has better suspension rate and dispersibility. This may be because SD-819 has a comb-shaped structure, with a lipophilic long-chain skeleton and a hydrophilic low-molecular graft copolymer. The hydrophobic benzene rings, carbon chains and hydrophilic side chains in the skeleton, and the terminal -COO -The hydrophobic end groups are spread and adsorbed at the air-water interface. The mutual repulsion between the hydrophobic end groups is small, the side chains are highly hydrophilic, and the stacking is tight. Stable micelles are formed in the solution, and the active ingredients are strongly adsorbed. After the water-dispersible granules disintegrate, the lipophilic skeleton long chains fully wrap the pesticide active ingredient particles, and the hydrophilic comb-shaped structure forms an effective space barrier, quickly forming a stable system with long carbon chains wrapping the active ingredients and stable space steric hindrance. At the same time, the polycarboxylate dispersant SD-819 has a large number of adsorption sites, which will be adsorbed on the surface of the active ingredient particles, improve their surface properties, and reduce the agglomeration between particles, thereby effectively ensuring the suspension performance of the dispersed system.

[0013] The inventor unexpectedly discovered that, especially when the content of the dispersant is 1-6%, it has an excellent suspension and dispersion effect, and at this time, it can also effectively enhance the thixotropy of the water-dispersible granules and enhance the insecticidal effect when used. The inventor analyzed that it may be because the specific content of the polycarboxylate dispersant SD-819 can work together with other components in the system. After being subjected to shear force, the internal structure of the system can be quickly rearranged, and the long carbon chain wraps the active ingredient particles, so that the active ingredient is also quickly dispersed and uniform, and the original drug particle size is not easy to change during storage, and can maintain long-lasting suspension stability; and when used, it can effectively improve the distribution and adhesion of the active ingredient on the crop surface, increase the retention of pesticides on the crop surface, and prolong the retention time, thereby improving the biological activity of the pesticide, reducing the dosage, and improving the utilization rate of the liquid medicine. The inventor found in the experiment that if the content of the polycarboxylate dispersant SD-819 is too high, it will affect the dispersion stability of the water-dispersible granules. The inventors analyzed that this may be because when the adsorption of the dispersant on the active ingredient of the pesticide exceeds the saturation point, the excess ions in the solution enter the double layer, resulting in a decrease in electrostatic repulsion. The long-chain molecules of the dispersant may self-aggregate, resulting in agglomeration, flocculation and other problems, which in turn affects the suspension stability.

[0014] Preferably, the wetting agent is one or a mixture of alkyl sulfate, sodium alkylbenzene sulfonate, pull-opening powder (alkyl aryl sulfonate type surfactant), alkylphenol polyoxyethylene ether, phenethylphenol polyoxyethylene ether, succinate sulfonate, and fatty alcohol polyoxyethylene ether.

[0015] More preferably, the wetting agent is a mixture of one or more of alkyl sulfates and alkyl sulfonates.

[0016] Further preferably, the wetting agent is sodium lauryl sulfate.

[0017] Further preferably, the mass percentage of the wetting agent is 2-5%.

[0018] Preferably, the disintegrant is one or more combinations of sodium carboxymethyl starch, calcium chloride, sodium chloride, sodium carboxymethyl cellulose, soluble starch, ammonium sulfate, bentonite, and sodium polyacrylate.

[0019] In order to effectively increase the disintegration rate, it is further preferred that the disintegrant is soluble starch.

[0020] More preferably, the mass percentage of the disintegrant is 1-5%.

[0021] More preferably, the mass percentage of the disintegrant is 3%.

[0022] The inventors found that when soluble starch is used, the disintegration rate of the particles in water can be accelerated. Soluble starch has good water absorption. After absorbing water, it quickly swells and disintegrates in water. It can be completely dispersed into the original particle size, and the particle size after disintegration is uniform. The inventors unexpectedly found that when soluble starch is used as a disintegrant, the suspension stability and pourability of water-dispersible granules can be further improved. The inventors analyzed that it may be because it works together with other components in the system to achieve an effective balance between viscosity and suspension. When used, the active ingredients can be better dispersed and stably suspended in the solution, and have excellent pourability.

[0023] Preferably, the filler is a mixture of one or more of light calcium, diatomaceous earth, bentonite, kaolin, sepiolite, corn starch and ammonium sulfate.

[0024] Further preferably, the filler is corn starch.

[0025] Another invention of the present invention provides a production process of thiamethoxam water dispersible granules, and the specific steps are as follows:

[0026] S1: Pour the pesticide active ingredient, dispersant, wetting agent, disintegrant and filler into a stirring mixer and mix;

[0027] S2: pour the mixture of step S1 into a jet mill, grind it, pour it into a blender, add water and blend it in the blender for 10-20 minutes.

[0028] S3: Extruding and granulating the material obtained by stirring in step S2 by an extruder;

[0029] S4: The extruded particles are placed in an oven at 54° C. and dried for 0.5-2 hours. After drying, they are shaped and sieved to obtain the water dispersible granules.

[0030] Preferably, the mass of water added in step S2 is 15% of the mass of the mixture, and the stirring rate is 20-40 r / min.

[0031] More preferably, the extrusion temperature in step S3 is 30-40°C.

[0032] Compared with the prior art, the present invention has the following beneficial effects:

[0033] The 25% water dispersible granules of thiamethoxam prepared by the present invention have excellent and lasting suspension stability and dispersibility by using specific dispersants, disintegrants and other auxiliary ingredients, the suspension performance reaches more than 92.5%, and can be effectively stored, and it is not easy to have problems such as agglomeration and precipitation after long-term storage; it disintegrates quickly and finely in aqueous solution, can disintegrate completely, and there is no dead particle. The 25% water dispersible granules of thiamethoxam have excellent insecticidal effect when used, and the prevention effect can reach more than 90% 5 days after the drug is applied, and can effectively prevent and control various pests such as aphids, leafhoppers, planthoppers, whiteflies, beetle larvae, potato beetles, nematodes, ground beetles, leaf miners, and pests that develop resistance to various types of chemical pesticides. DETAILED DESCRIPTION

[0034] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be noted that the following embodiments are further descriptions of the present invention, rather than limitations of the present invention.

[0035] Example

[0036] Example 1

[0037] On one hand, the present embodiment provides a thiamethoxam water dispersible granule, which comprises, by mass percentage, 25% thiamethoxam, 5% dispersant, 3% wetting agent, 3% disintegrant, and filler supplemented to 100%.

[0038] Thiamethoxam was purchased from Shandong Xiangzhao New Materials Co., Ltd.; the dispersant was polycarboxylate dispersant SD-819, which was purchased from Shandong Xiangzhao New Materials Co., Ltd.; the wetting agent was sodium lauryl sulfate; the disintegrant was soluble starch; and the filler was corn starch.

[0039] On the other hand, this embodiment provides a production process of thiamethoxam water dispersible granules, and the specific steps are as follows:

[0040] S1: Pour the pesticide active ingredient, dispersant, wetting agent, disintegrant and filler into a stirring mixer and mix;

[0041] S2: pour the mixture of step S1 into a jet mill, grind it, pour it into the mixture and stir it, then add 15% of the mass of the mixture into water and stir it in a stirrer for 15 minutes at a stirring rate of 30 r / min;

[0042] S3: The material kneaded in step S2 is extruded into granules by an extruder at a temperature of 35°C.

[0043] S4: The extruded particles are placed in an oven at 54° C. and dried for 1 hour. After drying, they are shaped and sieved to obtain the water dispersible granules.

[0044] Example 2

[0045] On one hand, the present embodiment provides a thiamethoxam water dispersible granule, which comprises, by mass percentage, 25% thiamethoxam, 5% dispersant, 3% wetting agent, 5% disintegrant, and filler supplemented to 100%.

[0046] The sources of raw materials in this embodiment are the same as those in Example 1.

[0047] On the other hand, this embodiment provides a production process of thiamethoxam water dispersible granules, and the specific steps are the same as those in Example 1.

[0048] Example 3

[0049] On one hand, the present embodiment provides a thiamethoxam water dispersible granule, which comprises, by mass percentage, 25% thiamethoxam, 3% dispersant, 3% wetting agent, 3% disintegrant, and filler supplemented to 100%.

[0050] The sources of raw materials in this embodiment are the same as those in Example 1.

[0051] On the other hand, this embodiment provides a production process of thiamethoxam water dispersible granules, and the specific steps are the same as those in Example 1.

[0052] Comparative Example 1

[0053] This embodiment provides a thiamethoxam water dispersible granule, and its specific implementation method is the same as that of Example 1. The difference from Example 1 is that the dispersant is 5% calcium lignin sulfonate purchased from XX Company; and the disintegrant is 5% ammonium sulfate.

[0054] Comparative Example 2

[0055] This embodiment provides a thiamethoxam water dispersible granule, and its specific implementation manner is the same as that of Example 1, except that the disintegrant is 3% ammonium sulfate.

[0056] Comparative Example 3

[0057] This embodiment provides a thiamethoxam water dispersible granule, and its specific implementation manner is the same as that of Example 1. The difference from Example 1 is that the dispersant is 5% calcium lignin sulfonate purchased from XX Company.

[0058] Performance Testing

[0059] 1. Suspension rate test: Determine according to GB / T14825-2006.

[0060] 2. Disintegration test: Add 250 ml of standard hard water into a measuring cylinder, take 1 g of the water-dispersible granules in the above embodiments and comparative examples and pour them into the measuring cylinder. With the bottom of the measuring cylinder as the center, turn it upside down at a speed of 2 seconds / time, observe the disintegration state of the particles and record the complete disintegration time.

[0061] The water dispersible granules of Examples 1-3 and Comparative Examples 1-3 were tested for suspension and disintegration properties. The test results are shown in Table 1 below.

[0062] Table 1

[0063] Example Suspension rate Disintegration Example 1 93％ No dead particles, completely disintegrated Example 2 92％ No dead particles, completely disintegrated Example 3 92％ No dead particles, completely disintegrated Comparative Example 1 90％ A small amount of particles, not finely disintegrated Comparative Example 2 89％ A small amount of particles, not finely disintegrated Comparative Example 3 88％ A small amount of particles, not finely disintegrated

[0064] 3. Test results of tobacco aphid control

[0065] Calculation method of drug efficacy:

[0066]

[0067]

[0068]

[0069]

Claims

1. A thiamethoxam water dispersible granule, characterized in that: Calculated by mass percentage, the invention comprises 25% thiamethoxam, 3-5% dispersant, 1-8% wetting agent, 1-5% disintegrant, and filler supplemented to 100%; the dispersant is polycarboxylate dispersant SD-819; and the disintegrant is soluble starch.

2. The water dispersible granules of thiamethoxam according to claim 1, characterized in that: The wetting agent is one of alkyl sulfate, sodium alkylbenzene sulfonate, pull-opening powder, alkylphenol polyoxyethylene ether, phenethylphenol polyoxyethylene ether, succinate sulfonate, fatty alcohol polyoxyethylene ether, or a mixture of several of them.

3. The water dispersible granules of thiamethoxam according to claim 1, characterized in that: The filler is a mixture of one or more of light calcium, diatomaceous earth, bentonite, kaolin, sepiolite, corn starch and ammonium sulfate.

4. The production process of thiamethoxam water dispersible granules according to any one of claims 1 to 3, characterized in that: The specific steps are as follows: S1: Pour the pesticide active ingredient, dispersant, wetting agent, disintegrant and filler into a stirring mixer and mix; S2: pour the mixture of step S1 into a jet mill, grind it, pour it into the mixture and stir it, then add water and stir it in a stirrer for 10-20 minutes; S3: Extruding and granulating the material obtained by stirring in step S2 by an extruder; S4: The extruded particles are placed in an oven at 54° C. and dried for 0.5-2 hours. After drying, they are shaped and sieved to obtain the water dispersible granules.

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