CN101803599B - A kind of method for preparing biopesticide spinosyn microcapsule preparation - Google Patents

Abstract

The invention relates to a method for preparing biological pesticide spinosad microcapsule preparation, which comprises preparation of urea-formaldehyde prepolymer solution, preparation of spinosad mixture solution and preparation of spinosad microcapsule. The microcapsule preparation technique is simple and convenient, easy to control, stable in reaction, less in auxiliary additive, low in production cost and suitable for industrialized production. The spinosad prepared by the method has high coating efficiency, is not damaged by rainwater or does not have degradation phenomenon after being irradiated by light, has long slow release period, and prolongs the pest control period, thus not only improving the control effect, but also reducing the environmental pollution.

Description

A kind of method for preparing biopesticide spinosyn microcapsule preparation

technical field

The invention relates to a method for preparing a biopesticide spinosyn microcapsule preparation, which belongs to the technical field of pesticide preparation.

Background technique

The annual loss of global crops due to the threat of pests and diseases is about 1/3. At present, chemical pesticides still account for most of the market in the prevention and control of pests and diseases. With the extensive, long-term and repeated use of chemical pesticides, it not only causes huge pollution to soil, water and the atmosphere, but also directly endangers human health due to the increase of pesticide residues in agricultural by-products. Therefore, the development of safe, ecologically sustainable and environmentally friendly biopesticides has received widespread attention.

Spinosad is another kind of high-efficiency broad-spectrum insecticide after abamectin. It has both the safety of biological pesticides and the rapid effectiveness of chemically synthesized pesticides, and is environmentally friendly, and pests are not easy to develop drug resistance. It has become the focus of domestic research and development in recent years. Due to the existence of active ingredients in traditional pesticide formulations, they are prone to failure under the action of the external environment, and the duration of efficacy is short, which reduces the control effect of pesticides. Therefore, the development of pesticides needs to focus on solving the problem of new formulations of pesticides to improve the control effect of pesticides.

Contents of the invention

The technical problem to be solved by the present invention is to provide a method for preparing the spinosad microcapsule preparation of the biopesticide, the spinosad microcapsule preparation prepared by the preparation method overcomes that the existing spinosad preparation is easily degraded by light, and makes its drug effect Reduce and increase the amount of spraying, which is unfavorable to the ecological environment.

In order to solve the problems of the technologies described above, the technical solution adopted in the present invention is:

A method for preparing biopesticide spinosyn microcapsule preparation, the method may further comprise the steps:

a. Preparation of urea-formaldehyde prepolymer: Weigh urea and dissolve it in 30%-40% formaldehyde solution, the molar ratio of urea to formaldehyde is 1:1-2.5, fully stir until urea is completely dissolved, and adjust the pH to 7.0-2.5 9.0, heat up to 60 ℃ ~ 80 ℃, keep warm for 0.5 ~ 3.5 hours to form a viscous transparent liquid, then add distilled water to dilute, the volume ratio of formaldehyde solution to distilled water is 1: 1 ~ 3, to obtain stable urea-formaldehyde Prepolymer aqueous solution, in the preparation process, it is very important to control the reaction temperature, when the temperature is lower than the above range, the prepolymerization reaction is not complete, and prepolymer precipitation will be formed; when the temperature is higher than the above range, more side reactions will occur ;

b, the preparation of spinosyn mixture solution: dissolve spinosyn in organic solvent, the solid-liquid ratio of spinosyn and organic solvent is: weight: volume=1g: 20～50mL, stir to make spinosyn fully dissolve, Then add an emulsifier solution with a mass percentage of 0.5% to 2%, the volume ratio of the emulsifier solution to the organic solvent is 2 to 4:1, and then stir at 1000 to 2000r/min for 10 to 50 minutes to fully disperse the capsule core , when the mixed phase solution is clarified to form a stable O/W (oil/water) emulsion;

c. Preparation of spinosyn microcapsules: Add the urea-formaldehyde prepolymer aqueous solution to the spinosad mixture solution at room temperature, and use the urea-formaldehyde prepolymer aqueous solution and the dissolved spinosad The volume ratio of the organic solvent is 1-8:1, 1000-2000r/min, continue to stir for 10-50min to dissolve the prepolymer in the dispersion medium of the emulsion, then reduce the stirring speed to 500-900r/min, slowly Adjust the pH value of the solution, and reduce the pH value of the solution to 1.5-5.0 within 20-90 minutes. After the polycondensation reaction for 1-3 hours, add a dispersant solution with a mass percentage of 0.1%-1%. The mixture of the dispersant solution and the organic solvent The volume ratio is 1 to 2.5:1, and the temperature is raised to 40°C to 70°C, and the heat preservation reaction is continued for 2 to 5 hours, the heating is canceled, the reaction is stopped, and the pH of the reaction product is adjusted to 6 to 8. After cooling, filter and centrifuge, and dry. The spinosyn microcapsules prepared by the method are obtained. During the preparation process, factors such as stirring speed, pH and reaction temperature all have certain influences on the particle size and shape of the microcapsules. For example, the average particle size of microcapsules decreases with increasing stirring speed. When the polycondensation reaction is carried out under acid catalysis, the adding time and pH value of the acidifying agent should be strictly controlled. If the acidizing rate is too fast, gel will appear soon and microcapsules cannot be formed; if it is too slow, self-polymerizing particles will be produced. Therefore, the pH value of the reaction should be adjusted step by step, and the pH value should be controlled within the above-mentioned required range. At the same time, in the process of adding the acidic catalyst, the stirring speed needs to be reduced, otherwise the initially formed envelope is easily broken by high-intensity turbulent flow, thereby affecting the encapsulation efficiency of the microcapsules. In addition, the temperature at the later stage of the reaction should be higher than the temperature at the initial stage of the reaction, but it cannot exceed the boiling point of the capsule core material and the prepolymer. Controlling the above factors at the same time is the key to making microcapsules with small particle size, uniform distribution and smooth surface.

In the above preparation method, the organic solvent is selected from any one or more of petroleum ether, ethyl acetate, dichloromethane, chloroform, benzene, toluene, chlorobenzene or xylene.

The emulsifier is selected from sorbitan trioleate, sodium lignosulfonate, sodium lauryl sulfate, sodium dodecylbenzenesulfonate, calcium dodecylsulfonate, styrene-malay Any one or more of acid anhydride copolymer, NP-10, polyvinyl alcohol, polymer carboxylate, sodium fatty amido p-methoxybenzene sulfonate, gelatin, sodium carboxymethyl cellulose, naphthalene sulfonate kind.

The dispersant is selected from any one or more of polyvinyl alcohol, styrene-maleic anhydride copolymer sodium salt, sodium lignosulfonate, and sodium polyacrylate.

The acidic pH regulator used in the above preparation method is selected from hydrochloric acid, hydrochloric acid-potassium chloride buffer solution, citric acid or phosphoric acid. The alkaline pH regulator used is selected from triethanolamine, sodium hydroxide or ammonia water.

The above reactions were monitored using a photographic microscope during the microencapsulation process, and the prepared microcapsule products were identified.

The method of the present invention utilizes the microencapsulation technology to coat the active substance on the polymer-based material so as to release it slowly, improve the utilization efficiency of the drug, control and prolong the release period of the drug, and the like. The spinosyn microcapsule preparation prepared by the method has the following advantages:

(1) The yield is over 85%, the coating efficiency is high, and the sustained release period is long.

(2) The microencapsulation process is simple, easy to operate, stable in reaction, easy to control, less equipment investment, less auxiliary additives, low production cost, high market competitiveness, and is suitable for industrialized production.

(3) The release rate of spinosad can be controlled through the control of microencapsulation, which can prolong its control period for pests, improve the effective utilization rate, and consolidate the control effect.

(4) The prepared pesticide is not easily damaged by rainwater or degraded by light irradiation, and can effectively control the pollution of groundwater and reduce the impact on the environment.

The specific implementation manners of the present invention will be further described in detail below in conjunction with the accompanying drawings.

Description of drawings

Figure 1 is a microscope picture of spinosyn microcapsules.

Detailed ways

Example 1

Accurately weigh 24.0g of urea and add it to a three-necked flask, measure 40mL of 37% formaldehyde solution, stir at 1000r/min, stir until the urea is completely dissolved, add triethanolamine to adjust the pH to 8.0, gradually raise the temperature to 70°C, and keep stirring The speed and temperature are constant, and the reaction is stopped after 1 hour to form a viscous transparent liquid. Then, add distilled water about 2 times the volume of the formaldehyde solution to dilute to obtain a stable aqueous solution of urea-formaldehyde resin prepolymer.

Dissolve 1.0 g of spinosad in 10 mL of chloroform completely at room temperature, then add 15 mL of petroleum ether, stir and mix well, then add 70 mL of 0.7% by mass sodium lauryl sulfate aqueous solution as an emulsifier, Stir at 1000r/min for 10min to fully disperse and emulsify the capsule core. Then, add 75mL of the above-mentioned urea-formaldehyde resin prepolymer solution, 1000-2000r/min, continue to stir for 15min, then reduce the rotation speed to 700r/min, pump in the HCl-KCl buffer solution at a constant speed with a constant-flow pump, and adjust within 1h The pH of the reaction system was 2.0. After the polycondensation reaction for 1 hour, 50 mL of polyvinyl alcohol with a mass percentage of 0.4% was added as a dispersant. After the temperature was raised to 45°C to solidify the capsule wall for 2.5 hours, the heating was canceled to stop the reaction, and adjusted with NaOH solution. The pH of the reaction product reaches 7, after cooling, it is filtered, centrifuged and dried to obtain the spinosad microcapsules prepared by this method.

The encapsulation efficiency of the spinosyn microcapsule reaches more than 85%. Adopt microscope to observe prepared microcapsule product, as shown in Figure 1.

Example 2

Accurately weigh 40.0g of urea and add it to a three-necked flask, measure 100mL of 37% formaldehyde solution, stir at a speed of 1000r/min, stir until the urea is completely dissolved, add triethanolamine to adjust the pH to 8.0, gradually raise the temperature to 70°C, and keep stirring The speed and temperature are constant, and the reaction is stopped after 1 hour to form a viscous transparent liquid. Then, add distilled water about 2 times the volume of the formaldehyde solution to dilute to obtain a stable aqueous solution of urea-formaldehyde resin prepolymer.

Dissolve 1.5g of spinosad in 25mL of chloroform completely at room temperature, then add 35mL of petroleum ether, stir and mix thoroughly, then add 120mL of styrene-maleic anhydride copolymer with a mass percentage of 0.7% as an emulsifier , Stir at 1000r/min for 10min to fully disperse and emulsify the capsule core. Then, add 240mL of the above-mentioned urea-formaldehyde resin prepolymer solution, 1000-2000r/min, continue to stir for 15min, then reduce the rotation speed to 700r/min, pump in 10% citric acid solution at a constant speed with a constant flow pump, and adjust within 1h The pH of the reaction system was 2.0. After the polycondensation reaction for 1 hour, 75 mL of polyvinyl alcohol with a mass percentage of 0.4% was added as a dispersant. After the temperature was raised to 45°C to solidify the capsule wall for 2.5 hours, the heating was canceled to stop the reaction, and adjusted with NaOH solution. The pH of the reaction product reaches 7, after cooling, it is filtered, centrifuged and dried to obtain the spinosad microcapsules prepared by this method.

The encapsulation efficiency of the spinosad microcapsules is over 85%. The prepared microcapsule products were observed with a microscope.

Example 3

Accurately weigh 36.0g of urea and add it to a three-necked flask, measure 60mL of 37% formaldehyde solution, stir at 1000r/min, stir until the urea is completely dissolved, add NaOH solution to adjust the pH to 8.5, gradually raise the temperature to 80°C, and keep stirring The speed and temperature are constant, and the reaction is stopped after 1 hour to form a viscous transparent liquid. Then, add distilled water about 2 times the volume of the formaldehyde solution to dilute to obtain a stable aqueous solution of urea-formaldehyde resin prepolymer.

Dissolve 1.0 g of spinosad in 30 mL of petroleum ether completely at room temperature, stir and mix thoroughly, add 120 mL of an aqueous solution of sodium dodecylbenzenesulfonate with a mass percentage of 0.1% as an emulsifier, and stir at 1000 r/min for 10 min. Fully disperse and emulsify the capsule core. Then, add 150mL of the above-mentioned urea-formaldehyde resin prepolymer solution, 1000-2000r/min, continue to stir for 15min, then reduce the rotational speed to 700r/min, pump in the HCl-KCl buffer solution at a constant speed with a constant-flow pump, and adjust within 20min. The pH of the reaction system was 2.5. After 1.5 hours of polycondensation reaction, 60 mL of polyvinyl alcohol with a mass percentage of 0.4% was added as a dispersant. After the temperature was raised to 70°C to solidify the capsule wall for 3 hours, the heating was canceled and the reaction was stopped, and the reaction was adjusted with ammonia water. The pH of the product reaches 8, and after cooling, it is filtered, centrifuged, and dried to obtain the spinosad microcapsules prepared by this method.

The encapsulation efficiency of the spinosyn microcapsule reaches more than 85%. The prepared microcapsule products were observed with a microscope.

Example 4

Accurately weigh 40.0g of urea and add it to a three-necked flask, measure 100mL of 37% formaldehyde solution, stir at a speed of 1000r/min, stir until the urea is completely dissolved, add triethanolamine to adjust the pH to 8.0, gradually raise the temperature to 60°C, and keep stirring The speed and temperature are constant, and the reaction is stopped after 1 hour to form a viscous transparent liquid. Then, add distilled water about 3 times the volume of the formaldehyde solution to dilute to obtain a stable aqueous solution of urea-formaldehyde resin prepolymer.

Dissolve 1.5g of spinosad in 60mL of ethyl acetate completely at room temperature, stir and mix thoroughly, add 120mL of sorbitan trioleate with a mass percentage of 1% as an emulsifier, stir at 1000r/min for 10min, Fully disperse and emulsify the capsule core. Then, add 240mL of the above-mentioned urea-formaldehyde resin prepolymer solution, 1000-2000r/min, continue to stir for 15min, then reduce the rotation speed to 500r/min, pump in 10% citric acid solution at a constant speed with a constant-flow pump, and adjust within 1h The pH of the reaction system was 2.0. After the polycondensation reaction for 1 hour, 75 mL of sodium polyacrylate with a mass percentage of 0.4% was added as a dispersant. After the temperature was raised to 45°C to solidify the capsule wall for 2 hours, the heating was cancelled, the reaction was stopped, and the reaction was adjusted with NaOH solution. The pH of the product reaches 7, and after cooling, it is filtered, centrifuged, and dried to obtain the spinosad microcapsules prepared by this method.

The encapsulation efficiency of the spinosad microcapsules is over 85%. The prepared microcapsule products were observed with a microscope.

Apparently, the above-mentioned embodiments of the present invention are only examples for clearly illustrating the present invention, rather than limiting the implementation of the present invention. For those of ordinary skill in the art, other changes or changes in different forms can be made on the basis of the above description. All the implementation manners cannot be exhaustively listed here. All obvious changes or variations derived from the technical solutions of the present invention are still within the protection scope of the present invention.

Claims (4)

1. A method for preparing biopesticide spinosyn microcapsule preparation, characterized in that the method may further comprise the steps: a. Preparation of urea-formaldehyde prepolymer: Weigh urea and dissolve it in 30%-40% formaldehyde solution, the molar ratio of urea to formaldehyde is 1:1-2.5, fully stir until urea is completely dissolved, and adjust the pH to 7.0-2.5 9.0, heat up to 60 ℃ ~ 80 ℃, keep warm for 0.5 ~ 3.5 hours to form a viscous transparent liquid, then add distilled water to dilute, the volume ratio of formaldehyde solution to distilled water is 1: 1 ~ 3, to obtain stable urea-formaldehyde Prepolymer aqueous solution; b, the preparation of spinosyn mixture solution: dissolve spinosyn in organic solvent, the solid-liquid ratio of spinosyn and organic solvent is: weight: volume=1g: 20～50mL, stir to make spinosyn fully dissolve, Then add an emulsifier solution with a mass percentage of 0.5% to 2%, the volume ratio of the emulsifier solution to the organic solvent is 2 to 4:1, then stir at 1000 to 2000r/min for 10 to 50min, when the mixed phase solution is clear After forming a stable O/W (oil/water) emulsion; c. Preparation of spinosyn microcapsules: Add the urea-formaldehyde prepolymer aqueous solution to the spinosad mixture solution at room temperature, and use the urea-formaldehyde prepolymer aqueous solution and the dissolved spinosad The volume ratio of the organic solvent is 1-8:1, 1000-2000r/min, continue to stir for 10-50min to dissolve the prepolymer in the dispersion medium of the emulsion, then reduce the stirring speed to 500-900r/min, slowly Adjust the pH value of the solution, and reduce the pH value of the solution to 1.5-5.0 within 20-90 minutes. After the polycondensation reaction for 1-3 hours, add a dispersant solution with a mass percentage of 0.1%-1%. The mixture of the dispersant solution and the organic solvent The volume ratio is 1 to 2.5:1, and the temperature is raised to 40°C to 70°C, and the heat preservation reaction is continued for 2 to 5 hours, the heating is canceled, the reaction is stopped, and the pH of the reaction product is adjusted to 6 to 8. After cooling, filter and centrifuge, and dry. The spinosad microcapsules prepared by the method are obtained; Wherein, the organic solvent is selected from any one or more of petroleum ether, ethyl acetate, methylene chloride, chloroform, benzene, toluene, chlorobenzene or xylene; the emulsifier is selected from the group consisting of sorrel Alcohol Trioleate, Sodium Lignosulfonate, Sodium Lauryl Sulfate, Sodium Dodecylbenzene Sulfonate, Calcium Dodecyl Sulfonate, Styrene-Maleic Anhydride Copolymer, Polymer Carboxylate , any one or more of fatty amido sodium p-methoxybenzene sulfonate, and naphthalene sulfonate. 2. the method for preparing biopesticide spinosad microcapsule preparation according to claim 1, is characterized in that described dispersant is selected from polyvinyl alcohol, styrene-maleic anhydride copolymer sodium salt, sodium lignosulfonate, polyvinyl alcohol Any one or more of sodium acrylates. 3. The method for preparing the biopesticide spinosyn microcapsule preparation according to claim 1, wherein the acidic pH regulator is selected from hydrochloric acid, hydrochloric acid-potassium chloride buffer solution, citric acid or phosphoric acid. 4. the method for preparing biopesticide spinosad microcapsule preparation according to claim 1 is characterized in that alkaline pH regulator is selected from triethanolamine, sodium hydroxide or ammoniacal liquor.

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