Diuron water dispersible granule containing composite dispersing agent and preparation method of diuron water dispersible granule

Abstract

The invention belongs to the technical field of water dispersible granules, and provides a diuron water dispersible granule containing a composite dispersant and a preparation method thereof, the diuron water dispersible granule comprises the following components by weight: 50-70 parts of a diuron active compound, 6-10 parts of a composite dispersant, 5-6 parts of a wetting agent, 5-10 parts of a disintegrating agent, 1-3 parts of a binder, and 15-18 parts of a filler. The preparation method comprises the following steps: weighing according to the weight parts, crushing the diuron active compound by using a jet mill, adding the crushed diuron active compound, the composite dispersant, the wetting agent, the disintegrating agent, the binder and the filler into a mixer, uniformly stirring and mixing, then dropwise adding water into the mixer until granular solids are generated, stopping stirring, and carrying out spray drying to obtain the diuron sustained-release tablet. And transferring the solid particles into a drying oven for drying, and sieving to obtain the diuron water dispersible granules.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of water dispersible granules, and particularly relates to a diuron water dispersible granule containing a composite dispersant and a preparation method thereof. BACKGROUND

[0002] Diuron is used for preventing and controlling non-cultivated area weeds and preventing weeds from spreading. The diuron water dispersible granule on the market is mixed with water for spraying. Due to environmental pollution, the water in the irrigation channel is mostly hard water containing a large amount of soluble calcium and magnesium compounds. The suspension rate of the traditional diuron water dispersible granule is affected by hard water, which affects the drug effect.

[0003] Water dispersible granules (WG) are an environmentally friendly pesticide dosage form, which has excellent dispersibility, suspensibility and stability, can rapidly disintegrate in water to form a stable suspension system to improve the utilization efficiency and control effect of pesticides. At present, the water dispersible granule is mainly composed of raw materials, dispersants, wetting agents, disintegrants, binders, fillers and other components. The selection of the additive is a key factor affecting the wettability, disintegrability and suspensibility of the water dispersible granule, and further affects the retention amount and retention time of the pesticide liquid on the plant surface and the penetration ability on the plant surface, and affects the biological activity of the pesticide. In order to achieve higher use efficiency of the pesticide, the pesticide liquid should be fully spread and retained on the target substance. Therefore, the pesticide liquid should have low surface tension, good wettability and permeability on the target surface. Otherwise, the pesticide liquid will be lost, which will inevitably affect the drug effect and directly cause serious pollution to the environment.

[0004] Due to the requirements of use efficiency, safety and environmental protection, the active ingredients in the pesticide water dispersible granule in the prior art gradually tend to use multiple components. With the gradual complexity of the components, the performance of the additive of the water dispersible granule, especially the dispersibility, is gradually improved.

[0005] The Chinese patent application file with the patent application number CN 108207980 A discloses a diuron water dispersible granule. The raw materials include diuron raw powder, wetting dispersant and filler. The content of the diuron raw powder is 92% to 93%, the content of the wetting dispersant is 2.5% to 3.5%, and the rest is the filler. The disintegrability of the diuron water dispersible granule in water is poor because the disintegrant is not added in the raw materials. Therefore, the diuron water dispersible granule is further optimized on the basis of the prior art. SUMMARY

[0006] In order to overcome the deficiencies of the existing diuron water dispersible granule in dispersibility and suspensibility, the present application develops a diuron water dispersible granule containing a composite dispersant and a preparation method thereof. The diuron water dispersible granule can effectively improve the utilization efficiency of the diuron water dispersible granule and realize the synergistic effect of the diuron control effect.

[0007] The object of the present application can be achieved by the following technical solutions. The present application provides a water dispersible granule of diuron containing a composite dispersant, comprising the following components in parts by weight: diuron 50-70 parts, composite dispersant 6-10 parts, humectant 5-6 parts, disintegrant 5-10 parts, binder 1-3 parts, and filler 15-18 parts. The composite dispersant is prepared by the following steps: Sodium-based montmorillonite and modified lignin are added to deionized water, stirred at room temperature for 24 hours, the pH is adjusted to 2-3 using hydrochloric acid, filtered, washed with deionized water until the pH is neutral, and dried in a vacuum drying oven at 80°C until the water content is 50%-60%, to obtain the composite dispersant. In the above technical solution, the modified lignin is used for intercalation reaction with the montmorillonite to obtain the composite dispersant, and the modified lignin is combined with the montmorillonite to increase the interlayer spacing and further increase the steric hindrance of the dispersant, thereby significantly improving the suspension stability of the dispersant to the dispersed substances; at the same time, the montmorillonite is low in price, effectively reducing the production cost of the composite dispersant, and is a high-performance, low-cost composite dispersant specially used for pesticide water dispersible granules, suitable for environmentally friendly formulations such as pesticide water dispersible granules.

[0008] As a further scheme of the present application, the amount ratio of sodium-based montmorillonite, modified lignin and deionized water is 3-3.5 g: 3-3.5 g: 100 mL.

[0009] As a further scheme of the present application, the modified lignin is prepared by the following steps: Dissolve the alkali lignin in a sodium hydroxide solution (concentration 1 mol / L, pH 10.7), heat to 60-65°C, slowly add a chloroacetic acid solution (concentration 1.5 mol / L) dropwise, control the dropwise addition to be completed within 0.5-0.6 hours, and continue to react for 2-2.5 hours to obtain the modified lignin. In the above technical solution, the carboxymethylated alkali lignin as an anionic dispersant can be adsorbed on the surface of the pesticide particles to form an effective adsorption layer, and then promote uniform dispersion of the particles through steric hindrance effect or electrostatic repulsion. At the same time, the adsorption process is a key prerequisite for achieving dispersion, and generally the higher the adsorption capacity of the dispersant, the more significant its dispersion effect. It is worth noting that both lignin and diuron molecules contain aromatic ring structures, which enables the carboxymethylated alkali lignin to have strong adsorption affinity with diuron raw material molecules through π-π stacking, and this characteristic enables it to have higher adsorption capacity on diuron particles, and finally a stable carboxymethylated alkali lignin-diuron composite system can be constructed, and the formation of this composite significantly enhances the dispersion performance of diuron.

[0010] As a further aspect of the present application, the alkali lignin, the sodium hydroxide solution and the chloroacetic acid solution are used in a ratio of 9.8-10g:80mL:40mL.

[0011] As a further aspect of the present application, the wetting agent is at least one of polyethylene glycol, polyvinyl imine and sodium polyacrylate; and the disintegrating agent is at least one of sodium tripolyphosphate, sodium carboxymethyl starch and microcrystalline cellulose.

[0012] As a further aspect of the present application, the binder is at least one of sodium polyacrylate, carboxymethyl cellulose, polyvinyl alcohol, polyvinyl pyrrolidone, xanthan gum and sucrose.

[0013] As a further aspect of the present application, the filler is at least one of talc, kaolin, sawdust and white carbon black.

[0014] The present application provides a preparation method of a diuron water dispersible granule containing a composite dispersant, comprising the following steps: The diuron raw material is pulverized by an air flow pulverizer, and the pulverized diuron raw material, the composite dispersant, the wetting agent, the disintegrating agent, the binder and the filler are added into a mixing machine and stirred to be uniformly mixed, then water is added drop by drop into the mixing machine until granular solid is formed, the stirring is stopped, and the solid particles are transferred into an oven for drying at 55℃ for 0.5h, and then sieved to obtain the diuron water dispersible granule.

[0015] As a further aspect of the present application, the air flow pulverizer is pulverized to an average particle size of <5μm.

[0016] As a further aspect of the present application, the water is used in an amount of 18%-23% of the total mass of the medicament.

[0017] The present application has the following advantages: (1) The present application provides a diuron water dispersible granule containing a composite dispersant, which uses diuron raw material as the main material, and adds specific components of dispersant, wetting agent, disintegrating agent, binder and filler, and various components synergize with each other, so that the prepared diuron raw material water dispersible granule has a high suspension rate of >95.8%, a disintegration time of <46s and a dispersion rate of >92%, and has good suspension, disintegration and wetting properties. The present application also effectively improves the utilization rate of the active ingredient of diuron raw material, reduces the use dosage, reduces the cost, and is suitable for popularization and use.

[0018] (2) The application provides a composite dispersant, which is obtained by carrying out intercalation reaction on montmorillonite by modified lignin, and the modified lignin is combined with the montmorillonite, so that the interlayer spacing is increased, the steric hindrance of the dispersant is increased, and the suspension stability of the dispersant to the dispersed substance is significantly improved; meanwhile, the montmorillonite is low in price, and the production cost of the composite dispersant is effectively reduced, so that the composite dispersant is a special composite dispersant for high-performance and low-cost pesticide water dispersible granules, and is suitable for pesticide water dispersible granules and other environmentally-friendly formulations. Further, the composite dispersant is synergistically combined with the wetting agent, the disintegrating agent, the binder and the filler in the components, so that the suspension, the disintegration and the storage stability of the diuron water dispersible granules are significantly improved. DETAILED DESCRIPTION

[0019] The technical solutions of the application will be clearly and completely described below in combination with the embodiments. Apparently, the described embodiments are only some of the embodiments of the application, rather than all the embodiments. Based on the embodiments in the application, all the other embodiments obtained by those skilled in the art without creative work fall within the protection scope of the application.

[0020] EMBODIMENT

[0021] EMBODIMENT 1

[0022] The embodiment provides a diuron water dispersible granule containing a composite dispersant and a preparation method thereof. The diuron water dispersible granule containing the composite dispersant comprises the following components in parts by weight: 50 parts of diuron technical material, 6 parts of the composite dispersant, 5 parts of polyethylene glycol, 5 parts of sodium tripolyphosphate, 1 part of sodium polyacrylate and 15 parts of talc; The composite dispersant is prepared through the following steps: 9.8 g of alkali lignin is dissolved in 80 mL of sodium hydroxide solution (1 mol / L in concentration, and 10.7 in pH), and 40 mL of chloroacetic acid solution (1.5 mol / L in concentration) is slowly added dropwise under the condition of being controlled to be added dropwise within 0.5 h, and the reaction is continued for 2 h, so as to obtain modified lignin; 3 g of sodium-based montmorillonite and 3 g of modified lignin are added into 100 mL of deionized water, and stirring is conducted at room temperature for 24 h; hydrochloric acid is used to adjust the pH to 2, and then filtration and washing with deionized water are conducted until the pH is neutral; and the composite dispersant is obtained by drying in a vacuum drying box at 80 DEG C until the water content is 50%.

[0023] The preparation method of the diuron water dispersible granule containing the composite dispersant comprises the following steps: The diuron crude drug is weighed by weight parts, and is crushed by an airflow crusher to an average particle size of <5 μm. The crushed diuron crude drug, the composite dispersant, the wetting agent, the disintegrating agent, the binder and the filler are added into a mixer and stirred to mix uniformly. Then, water is added dropwise into the mixer until granular solid is formed. The amount of water is 18% of the total mass of the medicament. The stirring is stopped, and the solid particles are transferred into an oven for drying at 55°C for 0.5 h. The diuron water dispersible granules are obtained by sieving.

[0024] Example 2

[0025] The only difference between the example 1 and the example 2 is that: The composite dispersant is prepared by the following steps: 10 g of alkali lignin is dissolved into 80 mL of sodium hydroxide solution (concentration of 1 mol / L, pH of 10.7), and is heated to 60°C. Then, 40 mL of chloroacetic acid solution (concentration of 1.5 mol / L) is slowly added dropwise within 0.5 h. The reaction is continued for 2 h to obtain modified lignin. 3 g of sodium-based montmorillonite and 3 g of modified lignin are added into 100 mL of deionized water, and are stirred at room temperature for 24 h. The pH is adjusted to 2 by using hydrochloric acid. The mixture is filtered and washed with deionized water until the pH is neutral. The mixture is dried in a vacuum drying oven at 80°C until the water content is 50% to obtain the composite dispersant.

[0026] Example 3

[0027] The only difference between the example 1 and the example 3 is that: The composite dispersant is prepared by the following steps: 9.8 g of alkali lignin is dissolved into 80 mL of sodium hydroxide solution (concentration of 1 mol / L, pH of 10.7), and is heated to 60°C. Then, 40 mL of chloroacetic acid solution (concentration of 1.5 mol / L) is slowly added dropwise within 0.5 h. The reaction is continued for 2 h to obtain modified lignin. 3.5 g of sodium-based montmorillonite and 3.5 g of modified lignin are added into 100 mL of deionized water, and are stirred at room temperature for 24 h. The pH is adjusted to 2 by using hydrochloric acid. The mixture is filtered and washed with deionized water until the pH is neutral. The mixture is dried in a vacuum drying oven at 80°C until the water content is 50% to obtain the composite dispersant.

[0028] Example 4

[0029] The only difference between the example 1 and the example 4 is that: A diuron water dispersible granule containing a composite dispersant includes the following components by weight parts: 60 parts of diuron crude drug, 8 parts of composite dispersant, 5.5 parts of polyethylene glycol, 7 parts of sodium tripolyphosphate, 2 parts of sodium polyacrylate, and 16 parts of talc.

[0030] Example 5

[0031] The only difference compared with Example 1 is that: A water dispersible granule of diuron containing a composite dispersant, comprising the following components by weight: Diuron technical 70 parts, composite dispersant 10 parts, polyethylene glycol 6 parts, sodium tripolyphosphate 10 parts, sodium polyacrylate 3 parts, talc 18 parts.

[0032] Example 6

[0033] The only difference compared with Example 1 is that: A method for preparing a water dispersible granule of diuron containing a composite dispersant, comprising the following steps: Take by weight, diuron technical is crushed by air flow crusher, and the average particle size is crushed to <5 μm. The crushed diuron technical, composite dispersant, wetting agent, disintegrating agent, binder and filler are added into a mixer and stirred and mixed uniformly. Then water is added dropwise into the mixer until granular solid is formed. The amount of water is 20% of the total mass of the medicament. Stop stirring, and transfer the solid particles to an oven at 55°C for 0.5 h. Sieve to obtain the water dispersible granule of diuron.

[0034] Example 7

[0035] The only difference compared with Example 1 is that: A method for preparing a water dispersible granule of diuron containing a composite dispersant, comprising the following steps: Take by weight, diuron technical is crushed by air flow crusher, and the average particle size is crushed to <5 μm. The crushed diuron technical, composite dispersant, wetting agent, disintegrating agent, binder and filler are added into a mixer and stirred and mixed uniformly. Then water is added dropwise into the mixer until granular solid is formed. The amount of water is 20% of the total mass of the medicament. Stop stirring, and transfer the solid particles to an oven at 55°C for 0.5 h. Sieve to obtain the water dispersible granule of diuron.

[0036] Comparative Example

[0037] Comparative Example 1

[0038] The only difference compared with Example 1 is that: A water dispersible granule of diuron containing a composite dispersant, comprising the following components by weight: Diuron technical 70 parts, composite dispersant 10 parts, polyethylene glycol 6 parts, sodium tripolyphosphate 10 parts, sodium polyacrylate 3 parts, talc 18 parts.

[0039] Comparative Example 2

[0040] The only difference compared with Example 1 is that: A water dispersible granule of diuron containing a complex dispersant, comprising by weight parts: Diuron technical 50 parts, complex dispersant 4.5 parts, polyethylene glycol 5 parts, sodium tripolyphosphate 5 parts, sodium polyacrylate 1 part, talc 15 parts Comparative Example 3 The only difference from Example 1 is that: A water dispersible granule of diuron containing a complex dispersant, comprising by weight parts: Diuron technical 50 parts, complex dispersant 6 parts, polyethylene glycol 5 parts, sodium tripolyphosphate 5 parts, sodium polyacrylate 1 part, talc 15 parts.

[0041] Comparative Example 4

[0042] The only difference from Example 1 is that: A water dispersible granule of diuron containing a complex dispersant, comprising by weight parts: Diuron technical 50 parts, complex dispersant 13 parts, polyethylene glycol 5 parts, sodium tripolyphosphate 5 parts, sodium polyacrylate 1 part, talc 15 parts.

[0043] Comparative Example 5

[0044] The only difference from Example 1 is that: A water dispersible granule of diuron containing a complex dispersant, comprising by weight parts: Diuron technical 50 parts, complex dispersant 6 parts, sodium tripolyphosphate 5 parts, sodium polyacrylate 1 part, talc 15 parts.

[0045] Comparative Example 6

[0046] The only difference from Example 1 is that: A water dispersible granule of diuron containing a complex dispersant, comprising by weight parts: Diuron technical 50 parts, complex dispersant 6 parts, polyethylene glycol 5 parts, sodium polyacrylate 1 part, talc 15 parts Comparative Example 7 The only difference from Example 1 is that: A method for preparing a water dispersible granule of diuron containing a complex dispersant, comprising the steps of: The diuron raw material is pulverized by using an air flow pulverizer, and the pulverized diuron raw material, the composite dispersant, the wetting agent, the disintegrant, the binder and the filler are added into a mixer and stirred and mixed uniformly. Then water is added drop by drop into the mixer until granular solid is formed. The amount of water is 18% of the total mass of the medicament. The stirring is stopped, and the solid particles are transferred into an oven for drying at 55°C for 0.5h. The diuron water dispersible granules are obtained by sieving.

[0047] Comparative Example 8

[0048] The only difference compared with Example 1 is that: A preparation method of diuron water dispersible granules containing a composite dispersant, comprising the following steps: The diuron raw material is pulverized by using an air flow pulverizer, and the pulverized diuron raw material, the composite dispersant, the wetting agent, the disintegrant, the binder and the filler are added into a mixer and stirred and mixed uniformly. Then water is added drop by drop into the mixer until granular solid is formed. The amount of water is 15% of the total mass of the medicament. The stirring is stopped, and the solid particles are transferred into an oven for drying at 55°C for 0.5h. The diuron water dispersible granules are obtained by sieving.

[0049] Comparative Example 9

[0050] The only difference compared with Example 1 is that: A preparation method of diuron water dispersible granules containing a composite dispersant, comprising the following steps: The diuron raw material is pulverized by using an air flow pulverizer, and the pulverized diuron raw material, the composite dispersant, the wetting agent, the disintegrant, the binder and the filler are added into a mixer and stirred and mixed uniformly. Then water is added drop by drop into the mixer until granular solid is formed. The amount of water is 26% of the total mass of the medicament. The stirring is stopped, and the solid particles are transferred into an oven for drying at 55°C for 0.5h. The diuron water dispersible granules are obtained by sieving.

[0051] Performance test

[0052] The diuron water dispersible granules prepared in Example 1-Example 7 and Comparative Example 1-Comparative Example 9 are subjected to performance test, and the test results are shown in Table 1. Table 1

[0053] As shown in Table 1, the suspensibility, disintegration time, dispersibility and effective period of the diuron water dispersible granules prepared in Examples 1-7 are significantly better than those of the diuron water dispersible granules prepared in Comparative Examples 1-9, and the data fluctuation is smaller, which shows higher stability and better dispersing performance. It can be seen that the diuron water dispersible granules containing the composite dispersing agent and the preparation method thereof provided in the application significantly improve the comprehensive performance of the diuron water dispersible granules, and have better application prospect.

[0054] It should be noted that the relational terms herein such as first and second and the like are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any such actual relationship or order between such entities or actions. Moreover, the terms "comprises", "comprising", or any other variations thereof, are intended to cover a non-exclusive inclusion such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but can include other elements not expressly listed or inherent to such process, method, article, or apparatus.

[0055] Although the embodiments of the present application have been shown and described, it is to be understood that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present application, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A water dispersible granule of diuron containing a complex dispersant, characterized in that, The granules comprise the following components by weight: diuron 50-70 parts, a composite dispersant 6-10 parts, a wetting agent 5-6 parts, a disintegrating agent 5-10 parts, a binder 1-3 parts, and a filler 15-18 parts. The composite dispersant is prepared by the following steps: Sodium-based montmorillonite and modified lignin are added to deionized water, stirred at room temperature for 24 hours, the pH is adjusted to 2-3, filtered, washed until the pH is neutral, and vacuum dried to a moisture content of 50-60%, to obtain the composite dispersant.

2. The diuron water dispersible granule containing a complex dispersing agent according to claim 1, characterized by, The amount ratio of sodium-based montmorillonite, modified lignin, and deionized water is 3-3.5 g: 3-3.5 g: 100 mL.

3. The diuron water dispersible granule containing a complex dispersing agent according to claim 1, characterized by, The modified lignin is prepared by the following steps: The alkali lignin is dissolved in a sodium hydroxide solution, heated to 60-65°C, and slowly added with a chloroacetic acid solution, which is added dropwise within 0.5-0.6 hours, and the reaction is continued for 2-2.5 hours to obtain the modified lignin.

4. The diuron water dispersible granule containing a complex dispersing agent according to claim 3, characterized by, The amount ratio of alkali lignin, sodium hydroxide solution, and chloroacetic acid solution is 9.8-10 g: 80 mL: 40 mL.

5. The diuron water dispersible granule containing a complex dispersing agent according to claim 1, characterized by, The wetting agent is at least one of polyethylene glycol, polyethylene imine, and sodium polyacrylate; and the disintegrating agent is at least one of sodium tripolyphosphate, sodium carboxymethyl starch, and microcrystalline cellulose.

6. The diuron water dispersible granule containing a complex dispersing agent according to claim 1, characterized by, The binder is at least one of sodium polyacrylate, carboxymethyl cellulose, polyvinyl alcohol, polyvinyl pyrrolidone, xanthan gum, and sucrose.

7. The diuron water dispersible granule containing a complex dispersing agent according to claim 1, characterized by, The filler is at least one of talc, pottery clay, sawdust, and white carbon black.

8. A process for the preparation of diuron water dispersible granules containing a complex dispersing agent according to claim 1, characterized by, The following steps are included: The diuron is weighed and ground by an air jet grinder, the ground diuron, composite dispersant, wetting agent, disintegrating agent, binder, and filler are added to a mixer and stirred until uniform, water is then added dropwise to the mixer until granular solids are formed, the stirring is stopped, the solid particles are transferred to an oven and baked at 55°C for 0.5 hours, and the granules are obtained by sieving.

9. A process for the preparation of diuron water dispersible granules containing a complex dispersing agent according to claim 8, characterized in that, The air jet grinder is used to grind the diuron to an average particle size of <5 μm.

10. A process for the preparation of diuron water dispersible granules containing a complex dispersing agent according to claim 8, characterized by, The amount of water is 18-23% of the total mass of the granules.

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