Preparation method and application of nonanoic acid microcapsule suspending agent

Abstract

The invention discloses a preparation method and application of a nonanoic acid microcapsule suspending agent, and relates to the technical field of herbicides. The nonanoic acid microcapsule suspending agent consists of nonanoic acid, white carbon black, an emulsifying agent, a dispersing agent, a thickening agent, an anti-freezing agent, a preservative, a de-foaming agent and de-ionized water. Wherein the nonanoic acid is adsorbed in pores in the white carbon black, and the emulsifier and the dispersing agent are coated on the surface of the white carbon black, so that the coating rate and the stability are relatively high. The formula parameters of the nonanoic acid microcapsule suspending agent comprise 10-30% of nonanoic acid, 4-15% of white carbon black, 1-5% of an emulsifier, 2-4% of a dispersing agent, 0.1-1% of a thickening agent, 3-4% of an anti-freezing agent, 0.1-0.3% of a preservative, 0.1-0.2% of a defoaming agent and the balance of deionized water. The prepared nonanoic acid microcapsule suspending agent is good in application in weed control, stable in component, environment-friendly and safe.

Description

Technical Field

[0001] The present invention relates to the technical field of herbicides, and specifically to a preparation method and application of a nonanoic acid microcapsule suspension. Background Art

[0002] Nonanoic acid is one of the 200 active ingredients notified in the fourth round of pesticide reviews in the European Union. It widely exists in animals and plants. In plants, it mostly exists in essential oils in the form of esters, and very few exist in the free state. It belongs to slightly toxic pesticides. It is reported that the residue time of nonanoic acid in the soil is only 3 days, which is easy to degrade and environmentally friendly. It can interfere with the structure of the cell membrane of the target organism, cause cell membrane rupture and cell death, and has the characteristics of "quick-acting, non-selective, and contact-killing", which has many similarities with the action mode and characteristics of paraquat. Nonanoic acid also has insecticidal and bactericidal effects, and can also be used as a flower and fruit thinning agent at low doses.

[0003] Currently, the nonanoic acid on the market is mainly 30% aqueous emulsion. Preparing this aqueous emulsion requires a large amount of organic solvents, which poses a major safety hazard in terms of safety and environmental protection. Although neutralizing nonanoic acid into sodium salts, potassium salts, various amine salts and modifying it by reacting with ethylene oxide can improve its water solubility and reduce the solvent consumption, it also loses its herbicidal activity. Therefore, how to reduce the solvent consumption and develop a more environmentally friendly and safe nonanoic acid herbicide without reducing the herbicidal activity has become a difficult point.

[0004] As a kind of slow-release dosage form, microcapsules are one of the dosage forms with the fastest development at present. It uses natural, semi-natural or synthetic coating materials and uses physical, chemical and physical-chemical combined methods to encapsulate the active ingredients of pesticides, which can improve the stability of the active ingredients, reduce the use toxicity, control the release, and achieve the purpose of reducing pesticide application and increasing efficiency. However, the microcapsules prepared by traditional methods are formed by chemical synthesis methods such as reacting urea with formaldehyde or isocyanates with polyamines to form a film on the surface of the substance to be coated. The process is complex, the cost is high, and the quality is unstable. Summary of the Invention

[0005] The purpose of the present invention is to provide a preparation method and application of a nonanoic acid microcapsule suspension to solve the problems raised in the prior art.

[0006] To achieve the above purpose, the present invention provides the following technical solutions: A preparation method of a nonanoic acid microcapsule suspension, comprising the following steps: After uniformly stirring nonanoic acid and silica white, successively add an emulsifier, a dispersant, a thickener, an antifreeze, a preservative, an antifoaming agent and deionized water and stir evenly, and perform high-speed shearing for 10-20 minutes; then sand-grind all the materials until the average particle size is less than 5 μm to obtain the nonanoic acid microcapsule suspension.

[0007] Furthermore, the dosage of silica white is 40 - 50 wt% of nonanoic acid.

[0008] High - speed shearing is carried out at 1200 - 1500 r / min.

[0009] The emulsifier is selected from at least one of polyoxyethylene polyol fatty acid esters, dodecylbenzenesulfonates, and betaines.

[0010] The dispersant is selected from at least one of triphenylvinylphenol polyoxyethylene ether phosphate, alkylphenol polyoxyethylene ether phosphate, ammonium salt of triphenylvinylphenol polyoxyethylene ether phosphate, sulfonated naphthalene formaldehyde condensate, sulfosuccinate, sodium lignosulfonate, calcium lignosulfonate, and sodium polycarboxylate.

[0011] The thickener is selected from at least one of xanthan gum, magnesium aluminum silicate, sodium carboxymethyl cellulose, polyvinyl alcohol, gelatin, chitosan, polymethacrylic acid, and polyacrylic acid.

[0012] The antifreeze is selected from at least one of ethylene glycol, glycerol, 1,2 - propanediol, and urea.

[0013] The preservative is selected from at least one of sodium benzoate, isothiazolinone, benzisothiazolinone, potassium sorbate, and quaternary ammonium salts.

[0014] The defoamer is selected from at least one of long - chain fatty alcohols, fatty acid esters, tributyl phosphate, polyethers, and silane polyethers.

[0015] Furthermore, the nonanoic acid microcapsule suspension is composed of the following components by weight percentage: nonanoic acid 10 - 30%, silica white 4 - 15%, emulsifier 1 - 5%, dispersant 2 - 4%, thickener 0.1 - 1%, antifreeze 3 - 4%, preservative 0.1 - 0.3%, defoamer 0.1% - 0.2%, and deionized water is added to make up 100%.

[0016] Furthermore, the application of a nonanoic acid microcapsule suspension prepared by the present invention in weed control.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. In the nonanoic acid microcapsule suspension prepared by the present invention, the microcapsules are composed of silica white adsorbing nonanoic acid. Silica white has a porous structure, a relatively high porosity, and strong adsorption ability. Compared with other chemically synthesized microcapsules, it is not easily damaged; nonanoic acid is firmly adsorbed inside the silica white, and the surfactant is coated on the surface of the silica white, having a high coating rate and stability; 2. The present invention uses silica white to adsorb nonanoic acid. Compared with the nonanoic acid aqueous emulsion on the market, it can ensure the herbicidal activity of nonanoic acid without using organic solvents, and is more environmentally friendly and safe; 3. The formulation of the nonanoic acid microcapsule suspension prepared by the present invention is reasonably designed, and the efficacy is stable. The coating of the surfactant effectively reduces the agglomeration of silica white and improves the storage stability. The synergistic effect of multiple components ensures the efficacy of the nonanoic acid microcapsule suspension. Detailed implementation manners

[0018] Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the scope of protection of the present invention.

[0019] In the experiments, the content of the nonanoic acid active ingredient was 98%, and the nonanoic acid mentioned in the following groups of experiments was all 98% nonanoic acid.

[0020] Example 1: This example provides a nonanoic acid microcapsule suspension, and the specific preparation steps are as follows: After uniformly stirring 20.41 g of nonanoic acid and 9 g of silica white, 3 g of sodium dodecylbenzenesulfonate, 3 g of sodium lignosulfonate, 0.2 g of xanthan gum, 3 g of ethylene glycol, 0.1 g of sodium benzoate, 0.1 g of silicone and 61.19 g of deionized water were successively added and stirred evenly, and sheared at 1500 r / min for 20 min; then all the materials were sanded until the average particle size was less than 5 μm to obtain the nonanoic acid microcapsule suspension. Example 2: Referring to the preparation process of Example 1, the difference is that the component of silica white is reduced, and the specific steps are as follows: After uniformly stirring 20.41 g of nonanoic acid and 8.2 g of silica white, 3 g of sodium dodecylbenzenesulfonate, 3 g of sodium lignosulfonate, 0.2 g of xanthan gum, 3 g of ethylene glycol, 0.1 g of sodium benzoate, 0.1 g of silicone and 61.99 g of deionized water were successively added and stirred evenly, and sheared at 1500 r / min for 20 min; then all the materials were sanded until the average particle size was less than 5 μm to obtain the nonanoic acid microcapsule suspension. Example 3: Referring to the preparation process of Example 1, the difference is that the component of silica white is increased, and the specific steps are as follows: After uniformly stirring 20.41 g of nonanoic acid and 10.2 g of silica white, 3 g of sodium dodecylbenzenesulfonate, 3 g of sodium lignosulfonate, 0.2 g of xanthan gum, 3 g of ethylene glycol, 0.1 g of sodium benzoate, 0.1 g of silicone and 59.99 g of deionized water were successively added and stirred evenly, and sheared at 1500 r / min for 20 min; then all the materials were sanded until the average particle size was less than 5 μm to obtain the nonanoic acid microcapsule suspension. Example 4: Referring to the preparation process of Example 1, the difference is that the emulsifier is adjusted from sodium dodecylbenzenesulfonate to Tween-80, and the specific steps are as follows: After uniformly stirring 20.41 g of nonanoic acid and 9 g of silica white, 3 g of Tween-80, 3 g of sodium lignosulfonate, 0.2 g of xanthan gum, 3 g of ethylene glycol, 0.1 g of sodium benzoate, 0.1 g of silicone and 61.19 g of deionized water were added in sequence and stirred evenly, and sheared at 1500 r / min for 20 min; then all the materials were sanded until the average particle size was less than 5 μm to obtain a nonanoic acid microcapsule suspending agent. Example 5: Referring to the preparation process of Example 1, the difference is that the emulsifier was adjusted from sodium dodecylbenzenesulfonate to lauramidopropyl betaine. The specific steps are as follows: After uniformly stirring 20.41 g of nonanoic acid and 9 g of silica white, 3 g of lauramidopropyl betaine, 3 g of sodium lignosulfonate, 0.2 g of xanthan gum, 3 g of ethylene glycol, 0.1 g of sodium benzoate, 0.1 g of silicone and 61.19 g of deionized water were added in sequence and stirred evenly, and sheared at 1500 r / min for 20 min; then all the materials were sanded until the average particle size was less than 5 μm to obtain a nonanoic acid microcapsule suspending agent. Example 6: Referring to the preparation process of Example 1, the difference is that the components of nonanoic acid, silica white and sodium dodecylbenzenesulfonate were adjusted. The specific steps are as follows: After uniformly stirring 10.2 g of nonanoic acid and 4.5 g of silica white, 2 g of sodium dodecylbenzenesulfonate, 3 g of sodium lignosulfonate, 0.2 g of xanthan gum, 3 g of ethylene glycol, 0.1 g of sodium benzoate, 0.1 g of silicone and 76.9 g of deionized water were added in sequence and stirred evenly, and sheared at 1500 r / min for 20 min; then all the materials were sanded until the average particle size was less than 5 μm to obtain a nonanoic acid microcapsule suspending agent. Example 7: Referring to the preparation process of Example 1, the difference is that the components of nonanoic acid, silica white and sodium dodecylbenzenesulfonate were adjusted. The specific steps are as follows: After uniformly stirring 30.61 g of nonanoic acid and 13.5 g of silica white, 4 g of sodium dodecylbenzenesulfonate, 3 g of sodium lignosulfonate, 0.2 g of xanthan gum, 3 g of ethylene glycol, 0.1 g of sodium benzoate, 0.1 g of silicone and 45.49 g of deionized water were added in sequence and stirred evenly, and sheared at 1500 r / min for 20 min; then all the materials were sanded until the average particle size was less than 5 μm to obtain a nonanoic acid microcapsule suspending agent. Comparative Example 1: A nonanoic acid microemulsion, and the specific formula is as follows: 30.61 g of nonanoic acid, 5 g of sodium dodecylbenzenesulfonate, 10 g of ammonium salt of triphenylethylphenol polyoxyethylene ether sulfonate and 54.39 g of ethanol were stirred into a clear and transparent liquid. Comparative Example 2: A nonanoic acid microemulsion, and the specific formula is as follows: Dissolve 7.5 g of potassium hydroxide in 60.59 g of deionized water, then add 20.41 g of nonanoic acid. Heat to 60 °C and stir until the reaction is complete. Add 3 g of sodium dodecylbenzenesulfonate, 5 g of ammonium tristyrylphenol polyoxyethylene ether sulfonate, and 3.5 g of sodium polyacrylate, and stir evenly. Comparative Example 3: A nonanoic acid microemulsion, with the specific formulation as follows: Stir 20.41 g of nonanoic acid, 10.9 g of monoethanolamine, and 57.19 g of deionized water evenly, heat to 65 °C, and stir until the reaction is complete. Add 3 g of sodium dodecylbenzenesulfonate, 5 g of ammonium tristyrylphenol polyoxyethylene ether sulfonate, and 3.5 g of sodium polyacrylate, and stir evenly. Detection test 1. Detect various indicators of the nonanoic acid microcapsule suspension prepared in Examples 1-5: (1) Determination of the encapsulation rate: Use high-performance liquid chromatography to determine the content of free nonanoic acid in each example, and calculate its encapsulation rate; (2) Determination of particle size: Conduct according to the agricultural industry standard NY / T 1860.32-2014; (3) Determination of suspension rate: Conduct according to the national standard GB / T 14825-2006; (4) Wet sieve determination: Conduct according to the national standard GB / T 16150-1995; (5) pH value determination: Conduct according to the national standard GB / T 1601; (6) Determination of persistent foaming property: Pour 200 ml of 342 ppm standard hard water into a 250 ml stoppered graduated cylinder, weigh 1 g of the preparation sample, invert the graduated cylinder up and down 30 times, and measure the foam height after 1 min; (7) Determination of freeze-thaw stability: Conduct according to the national standard GB / T 43273-2023; (8) Determination of thermal storage stability: Conduct according to the national standard GB / T 19136; (9) Determination of cold storage stability: Conduct according to the national standard GB / T 19137; In summary, the main technical reference indicators of the nonanoic acid microcapsule suspension prepared in the present invention are shown in Table 1 below: Table 1

[0021] The test results are shown in Table 2: Table 2

[0022] 2. Conduct non-cultivated land weeding experiments (1) Test agents Example 1, Example 4, Example 5, Example 6, Example 7, Comparative Example 1, Comparative Example 2, Comparative Example 3, and a clear water blank control group.

[0023] (2) Targets of prevention and treatment The test site is located in the summer non-cultivated land of Nanjing. The grass weeds in the test site mainly include Eleusine indica, Digitaria adscendens, etc., and the broadleaf weeds include Cynuracerepidioides, Amaranthus spinosus, etc. The weeds were divided into grass and broadleaf weeds to evaluate the efficacy.

[0024] (3) Treatment and application methods The experimental site was divided into 4 blocks, each block was divided into 9 plots, and each plot covered an area of 20m 2 Each treatment was randomly arranged and repeated 4 times. According to the activity intensity of the agent, 30% nonanoic acid active ingredient 20kg / hm 2 (Preparation dosage 66.7L / hm 2 ), 20% nonanoic acid active ingredient 20kg / hm 2 (Preparation dosage 100L / hm 2 ), 10% nonanoic acid active ingredient 20kg / hm 2 (Preparation dosage 200L / hm 2 ) and water blank control. Most weeds were in the peak growth period when the pesticide was applied, and conventional spraying was used with a water consumption of 750 L / hm 2 . It was sunny and there was no rainfall within 3 days after application.

[0025] (4) Survey methods The weed base was investigated on the day of spraying, and the efficacy was determined 3 days after spraying. Before spraying, four survey points with a comprehensive range of weed species were selected in each plot, and bamboo sticks were inserted to mark them. A square iron frame with a side length of 0.5 m was used to frame the fixed points, and 0.25 m was surveyed respectively. 2 The plant control effect and fresh weight control effect of grasses and broad-leaved weeds in the area.

[0026] (5) Results and analysis According to Table 3 below, nonanoic acid loses its herbicidal activity after neutralization. The efficacy of nonanoic acid microcapsule suspension is equivalent to that of nonanoic acid microemulsion. The weeds began to wilt 1 hour after application, and the weeds were basically withered 3 days after application. Most of the weeds were still withered 14 days after application, and the grass weeds began to grow new heart leaves.

[0027]

[0028] Conclusion: Based on the above two groups of detection experiments and their data, the nonanoic acid microcapsule suspension has excellent herbicidal effects, stable components, no organic solvents compared with the nonanoic acid microemulsion, is more environmentally friendly and safe, and can be promoted and applied.

[0029] Finally, it should be noted that the above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or perform equivalent replacements on some of the technical features. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A preparation method of a microcapsule suspension of nonanoic acid, characterized in that, It includes the following steps: After uniformly stirring nonanoic acid and silica white, successively add an emulsifier, a dispersant, a thickener, an antifreeze, a preservative, an antifoaming agent and deionized water and stir evenly, then perform high-speed shearing for 10 - 20 min; then grind all the materials until the average particle size is less than 5 μm to obtain a nonanoic acid microcapsule suspension.

2. The preparation method of a microcapsule suspension of nonanoic acid according to claim 1, characterized in that, The dosage of silica white is 40 - 50 wt% of nonanoic acid; the high-speed shearing is carried out at 1200 - 1500 r / min.

3. The preparation method of a microcapsule suspension of nonanoic acid according to claim 1, characterized in that, The emulsifier is selected from at least one of polyoxyethylene polyol fatty acid ester, dodecylbenzenesulfonate, and betaine; the dispersant is selected from at least one of triphenylvinylphenol polyoxyethylene ether phosphate, alkylphenol polyoxyethylene ether phosphate, ammonium salt of triphenylvinylphenol polyoxyethylene ether phosphate, naphthalene sulfonate formaldehyde condensate sulfonate, succinate sulfonate, sodium lignosulfonate, calcium lignosulfonate, and sodium polycarboxylate.

4. The preparation method of a microcapsule suspension of nonanoic acid according to claim 1, characterized in that, The thickener is selected from at least one of xanthan gum, magnesium aluminum silicate, sodium carboxymethyl cellulose, polyvinyl alcohol, gelatin, chitosan, polymethacrylic acid, and polyacrylic acid.

5. The preparation method of a microcapsule suspension of nonanoic acid according to claim 1, characterized in that, The antifreeze is selected from at least one of ethylene glycol, glycerol, 1,2 - propanediol, and urea.

6. The preparation method of a microcapsule suspension of nonanoic acid according to claim 1, characterized in that, The preservative is selected from at least one of sodium benzoate, isothiazolinone, benzisothiazolinone, potassium sorbate, and quaternary ammonium salts.

7. The preparation method of a microcapsule suspension of nonanoic acid according to claim 1, characterized in that, The antifoaming agent is selected from at least one of long-chain fatty alcohols, fatty acid esters, tributyl phosphate, polyethers, and silane polyethers.

8. A microcapsule suspension of nonanoic acid, characterized in that, It is prepared by the preparation method of a nonanoic acid microcapsule suspension according to any one of claims 1 - 7.

9. The microcapsule suspension of nonanoic acid according to claim 8, characterized in that, The nonanoic acid microcapsule suspension is composed of the following components by weight percentage: nonanoic acid 10 - 30%, silica white 4 - 15%, emulsifier 1 - 5%, dispersant 2 - 4%, thickener 0.1 - 1%, antifreeze 3 - 4%, preservative 0.1 - 0.3%, antifoaming agent 0.1% - 0.2%, and deionized water is made up to 100%.

10. Use of a nonanoic acid microcapsule suspension according to claim 8 in weed control.

Images