CN1663379A - Method for preparing pesticide avermectin microcapsule - Google Patents

Abstract

The invention relates to a pesticide formulation of nimbin and emamectin benzoate and preparing method belonging to the technology field of pesticide preparation, wherein the conventional in-situ polymerization method is improved for the preparing process, which comprises the preparation of ureaformaldehyde resin prepolymer aqueous solution, preparation of avermectin mixture solution and the preparation of avermectin microcapsule. The invention solves the problem of influenced drug effect by the combination of avermectin and soil, the drug effective period is also extended.

Description

A kind of method for preparing pesticide avermectin microcapsule

Technical field:

The present invention relates to a kind of method for preparing pesticide avermectin microcapsule, belong to the preparation technique of pesticide field.

Background technology:

At present, the new and effective agricultural chemicals of developing mainly comprises both at home and abroad, the one, and develop emerging high-efficiency low-toxicity chemical pesticide and change the formulation that has agricultural chemicals now, the 2nd, biopesticide.In conjunction with domestic actual conditions, China mainly concentrates on modified form and develops biopesticide.In the present domestic biopesticide jinggangmeisu of developing, pyrethrin, rotenone, nicotine, Avermectin etc., Avermectin is the best product of preventive effect, also is with fastest developing speed in the world at present, most widely used biopesticide.But in the development of present pesticide developing, Avermectin is as broad spectrum insecticide, be used for the biopesticide of the soil and the plant root extermination of disease and insect pest, mainly concentrate on missible oil, the development of conventional dosage forms such as supensoid agent, and these formulations make easily field planting in soil of Avermectin, therefore difficulty is given and is given full play to drug effect, and also injures natural enemy when killing off the insect pests, and destroys ecotope, contaminated environment more seriously is detrimental to health because of remaining in the crop.

As everyone knows, the method for making microcapsules is a lot, and the cyst material of selecting for use also has a lot.With regard to the preparation method of pesticide micro capsule, mainly concentrate on interfacial polymerization, coacervation, situ aggregation method now.Because the various advantages of situ aggregation method is widely adopted industrial.Relevant many patents of method therewith, the registration of existing 320 relevant situ aggregation methods up till now in EUROPEAN PATENT OFFICE's patent database typically has Japan's special permission 23 165/72,14 379/69,30282/71 etc.

Summary of the invention:

The objective of the invention is to overcome existing Avermectin preparation and be difficult to field planting in soil, drug effect is low, and consumption is big, and the deficiency of influence ecological environment adopts situ aggregation method to prepare the biological pesticide avermectin microcapsules.

The technical scheme of invention is: pesticide avermectin microcapsule adopts the situ aggregation method preparation, and operation comprises the preparation of performed polymer, the preparation of Avermectin mixture solution, the preparation of avermectin microcapsule, wherein:

A. the preparation of performed polymer: urea is dissolved in formaldehyde, the mol ratio of formaldehyde and urea is 2: 3～2: 5, with extremely clarification of magnetic stirrer, regulating pH value with triethanolamine is 8～9,65 ℃～70 ℃ of reaction temperatures, generate thick liquid after 1～1.5 hour reaction time, promptly get the stable urea-formaldehyde resin performed polymer aqueous solution with the distilled water diluting that doubles the formaldehyde consumption again;

B. the preparation of Avermectin mixture solution: will be powdery or granular Avermectin is dissolved in the solvent at the normal temperature state, solvent is carrene, chloroform, toluene or cyclohexanone, the solvent usage amount is so that till Avermectin dissolving or the dispersion, the 1g Avermectin is used 20～30ml solvent in this method.Adding 2%～10% emulsifier then fully disperses and emulsification, solution after solvent adds density again less than 1 benzinum, the consumption of benzinum is that the density of the avermectin microcapsule that generated equates with the density of water, under 60 ℃～90 ℃ temperature, after 1000r/min～1500r/min stirs, it is fully disperseed, after mixture mixes clarification, get final product;

C. the preparation of avermectin microcapsule: the urea-formaldehyde resin performed polymer aqueous solution is joined in the Avermectin mixture solution under 1000r/min～1500r/min stirs, after stirring 15min, to the HCl that wherein adds 1M slowly, mixing speed drops to 500r/min～750r/min, behind the 30min its pH value is transferred to 2.5, react and be warmed to 45 ℃ after one hour, react to cancel after 2.5 hours and heat, in reactant, add the 5ml Tween-20, and product is neutralized into pH=7 with NaOH, filter centrifugal collection avermectin microcapsule then; At last the microcapsules of gained are stored in the mixed solution of Tween-20 of 0.5% sodium carboxymethylcellulose and 1.9%.

Differentiate that the microcapsules that generated adopt microscopic examination.

The present invention compared with prior art, it is few to have an equipment investment, technology is easy to control, stable reaction is suitable for suitability for industrialized production, yield is higher than 80%, envelop rate is higher than 80%, and has advantages such as sustained release performance.The Avermectin capsule that this method is produced has not only solved Avermectin and has combined the problem that influences drug effect with soil, reduce consumption by slowly-releasing simultaneously, prolong the drug effect term of validity, consolidate control efficiency, be difficult for making agricultural chemicals by atmosphere, sunlight and rainwater destroy and run off, and effectively control prevents and treats the change of ecotope to phreatic pollution.

Description of drawings:

Fig. 1, Fig. 2 are the electron microscope picture of avermectin microcapsule.

Embodiment:

Embodiment 1:

The invention process device therefor is legacy equipment.

The preparation of performed polymer: precision weighing 12g urea is dissolved in (mol ratio of formaldehyde and urea is 2: 3) in the 24ml formaldehyde (37%) with it, at room temperature its pH value is transferred to 8.5 with triethanolamine, temperature is raised to 70 ℃ of reactions 1 hour, uses the 50ml distilled water diluting promptly to get the stable urea-formaldehyde resin performed polymer aqueous solution then;

The preparation of Avermectin mixture solution: precision weighing 1.5g Avermectin is dissolved in it in 25ml chloroform, adding 2% emulsifier then fully disperses and emulsification, solution after solvent adds density again less than 1 36ml benzinum, under 90 ℃ temperature, after 1000r/min stirs, it is fully disperseed, after mixture mixes clarification, get final product;

The preparation of avermectin microcapsule: the urea-formaldehyde resin performed polymer aqueous solution is joined in the Avermectin mixture solution under 1000r/min stirs, after stirring 15min, to the HCl that wherein adds 1M slowly, mixing speed drops to 750r/min, behind the 30min its pH value is transferred to 2.5, react and be warmed to 45 ℃ after one hour, react to cancel after 2.5 hours and heat, in reactant, add the 5ml Tween-20, and product is neutralized into pH=7 with NaOH, centrifugal then, filter and collect avermectin microcapsule; At last the microcapsules of gained are stored in the mixed solution of Tween-20 of 0.5% sodium carboxymethylcellulose and 1.9%.

Differentiate that the microcapsules that generated adopt microscopic examination.

Embodiment 2:

Substantially with embodiment 1.Difference is:

In the preparation section of performed polymer, precision weighing 12g urea is dissolved in (mol ratio of formaldehyde and urea is 2: 4) in the 30ml formaldehyde (37%) with it, and the pH value is 8, and reaction temperature is 65 ℃, and the reaction time is 1.2 hours;

The addition of emulsifier is 7% in the preparation section of Avermectin mixture solution, and temperature is 60 ℃, and mixing speed is 1200r/min;

The urea-formaldehyde resin performed polymer aqueous solution joins in the Avermectin mixture solution under 1200r/min stirs in the preparation section of avermectin microcapsule, stir 15min after, to the HCl that wherein adds 1M slowly, mixing speed drops to 500r/min.

Embodiment 3:

Substantially with embodiment 1.Difference is:

In the preparation section of performed polymer, precision weighing 12g urea is dissolved in (mol ratio of formaldehyde and urea is 2: 5) in the 37ml formaldehyde (37%) with it, and the pH value is 9, and reaction temperature is 68 ℃, and the reaction time is 1.5 hours;

The addition of emulsifier is 10% in the preparation section of Avermectin mixture solution, and temperature is 75 ℃, and mixing speed is 1500r/min

The urea-formaldehyde resin performed polymer aqueous solution joins in the Avermectin mixture solution under 1500r/min stirs in the preparation section of avermectin microcapsule, stir 15min after, to the HCl that wherein adds 1M slowly, mixing speed drops to 650r/min.

Claims (1)

1, a kind of method for preparing pesticide avermectin microcapsule adopts the situ aggregation method preparation, and operation comprises the preparation of performed polymer, the preparation of Avermectin mixture solution, the preparation of avermectin microcapsule, it is characterized in that:

A. the preparation of performed polymer: urea is dissolved in formaldehyde, the mol ratio of formaldehyde and urea is 2: 3～2: 5, with extremely clarification of magnetic stirrer, regulating pH value with triethanolamine is 8～9,65 ℃～70 ℃ of reaction temperatures, generate thick liquid after 1～1.5 hour reaction time, promptly get the stable urea-formaldehyde resin performed polymer aqueous solution with the distilled water diluting that doubles the formaldehyde consumption again;

B. the preparation of Avermectin mixture solution: will be powdery or granular Avermectin is dissolved in the solvent at the normal temperature state, solvent is carrene, chloroform, toluene or cyclohexanone, the solvent usage amount is so that till Avermectin dissolving or the dispersion, the 1g Avermectin is used 20～30ml solvent in this method; Adding 2%～10% emulsifier then fully disperses and emulsification, solution after solvent adds density again less than 1 benzinum, the consumption of benzinum is that the density of the avermectin microcapsule that generated equates with the density of water, under 60 ℃～90 ℃ temperature, after 1000r/min～1500r/min stirs, it is fully disperseed, after mixture mixes clarification, get final product;

C. the preparation of avermectin microcapsule: the urea-formaldehyde resin performed polymer aqueous solution is joined in the Avermectin mixture solution under 1000r/min～1500r/min stirs, after stirring 15min, to the HCl that wherein adds 1M slowly, mixing speed drops to 500r/min～750r/min, behind the 30min its pH value is transferred to 2.5, react and be warmed to 45 ℃ after one hour, react to cancel after 2.5 hours and heat, in reactant, add the 5ml Tween-20, and product is neutralized into pH=7 with NaOH, filter centrifugal collection avermectin microcapsule then; At last the microcapsules of gained are stored in the mixed solution of Tween-20 of 0.5% sodium carboxymethylcellulose and 1.9%.

Images