CN108029686A - A kind of pirimiphos-methyl microcapsule pesticide and preparation method thereof - Google Patents

Abstract

The invention discloses a pirimiphos-methyl microcapsule insecticide and a preparation method thereof, comprising the following raw materials in parts by weight: 90-100 parts of pirimiphos-methyl, TDI (toluene-2,4-diisocyanate) trimer 40-100 parts, chain extender 30-100 parts, emulsifier 30-50 parts and deionized water 1000-1100 parts. The surface of the microcapsules prepared by the present invention is dense and uniform, which overcomes the shortcoming that pirimiphos-methyl is easy to volatilize, protects the active ingredient of pirimiphos-methyl, and can control the release rate of pirimiphos-methyl by adjusting the core-wall ratio of the microcapsules The present invention improves the use efficiency of pirimiphos-methyl, reduces resource waste and environmental pollution, adopts TDI trimer as the oil phase monomer, and solves the problem of high volatility of diisocyanate monomers in the preparation process of polyurethane microcapsules The disadvantage is that it reduces the harm of chemical reagents to the human body during production, and overcomes the problems of formaldehyde in the cyst wall, cumbersome operation procedures, and long preparation process.

Description

A kind of pirimiphos-methyl microcapsule insecticide and preparation method thereof

technical field

The invention relates to the field of pesticide preparation, in particular to a pirimiphos-methyl microcapsule pesticide.

Background technique

The use of microcapsule technology to coat insecticides to prepare sustained-release pharmaceuticals has been widely used. Microcapsule technology is a technology that encapsulates substances in polymer films, and is a micro-package for storing solids, liquids, and gases. technology. Microcapsule technology originated in the 1930s and has developed very rapidly. Since the National CashRegister Company of the United States used microcapsule technology to make the first generation of carbonless copy paper in 1954, the application field of microcapsule technology has expanded to various fields such as agriculture, medicine, adhesives and liquid crystals: as in "X.Jia , W.B.Sheng, W.Li, Y.B.Tong, Z.Y.Liu, F.Zhou, ACS Appl Mater Interfaces 6 (2014) 19552-8", reported the preparation of pesticide microcapsules by using polydopamine-coated polybactin. The release of multivermectins from microcapsules has a pH-responsive property. In "W. Zhang, S. He, Y. Liu, Q. Geng, G. Ding, M. Guo, Y. Deng, J. Zhu, J. Li, Y. Cao, ACS Appl Mater Interfaces 6 (2014) 11783 -90", reported the use of silicon dioxide to coat prochloraz to prepare pesticide microcapsules, and the obtained microcapsules had uniform particle size and compact structure. In "B.Liu, Y.Wang, F.Yang, X.Wang, H.Shen, H.Cui, D.Wu, Colloids Surf B Biointerfaces 144(2016) 38-45", it is reported that the use of polylactic acid package Pesticide microcapsules were prepared by coating cyhalothrin, and the obtained microcapsules had good dispersibility. In "Y.Wang.Gao, F.Shen, Y.Li, S.Zhang, X.Ren, S.Hu, J Agric Food Chem 63(2015) 5196-204", it is reported that butyl acrylate and benzene Ethylene copolymers were used to coat chlorpyrifos to prepare pesticide microcapsules, and the resulting microcapsules could adjust the drug release rate by changing the copolymer components.

Pirimiphos-methyl is a high-efficiency, low-toxicity, broad-spectrum, quick-acting organophosphorus insecticide and acaricide, which can be widely used in household hygiene, public health and the control of crop pests. It has the advantages of fast knockdown and good effect. At the same time, it can be used as an effective substitute for phosphine to prevent and control storage pests. The dosage is low and there is basically no adverse reaction to the human body. It not only saves costs, but also has high efficiency and low toxicity. However, pirimiphos-methyl can be hydrolyzed by strong acid and alkali, and it is unstable to light. The choice of microcapsule suspension can protect its active ingredients from the influence of the external environment. Moreover, pirimiphos-methyl is mostly used in storage, household and public health, and economic crops such as flowers and fruits, so the capsule material of its microcapsules is required to be non-toxic and biodegradable. In "Li Yan, Deng Xinping, Xiong Haizheng, et al. Development of 20% pirimiphos-methyl microcapsule suspension [J]. Pesticide Research and Application, 2010, 14(4): 25-29" reported that urea-formaldehyde resin was used as wall material to coat pirimiphos-methyl to prepare Pesticide microcapsules have high encapsulation efficiency and good chemical stability, but there may be formaldehyde monomer in the microcapsules, which is harmful to human health. Gelatin Gum Arabic is used as the wall material to coat pirimiphos-methyl to prepare pesticide microcapsules. The obtained microcapsules have a high suspension rate and good stability. However, formaldehyde and toluene are used in the preparation process of the microcapsules, which is harmful to the environment and human health. . In "Li Min, Li Tao, Ou Xiaoming, Chen Jiuxing. Gao Hengxu Insecticide Pirimiphos-methyl Microcapsule Suspension and Preparation Method, Chinese Patent, CN102657160A" reported the use of chitosan-aliphatic polyester graft copolymer as The method of preparing insecticide pirimiphos-methyl microcapsules from the capsule wall, but the operation procedures are cumbersome, the preparation process takes a long time, and solvents such as volatile organic solvents such as dimethyl sulfoxide and methylene chloride are used, which are harmful to the environment and human health larger.

Contents of the invention

The object of the present invention is to provide a kind of pirimiphos-methyl microcapsule insecticide, to solve the problem raised in the above-mentioned background technology.

To achieve the above object, the present invention provides the following technical solutions:

A microcapsule insecticide of pirimiphos-methyl, comprising the following raw materials in parts by weight: 90-100 parts of pirimiphos-methyl, 40-100 parts of TDI (toluene-2,4-diisocyanate) trimer, chain extender 30-100 parts, 30-50 parts of emulsifier and 1000-1100 parts of deionized water.

As a further solution of the present invention: the emulsifier is an aqueous solution of styrene-maleic anhydride copolymer (SMA) with a mass fraction of 20%.

As a further solution of the present invention: the chain extender is at least one of 1,4-butanediol, polyethylene glycol 400, and polyethylene glycol 600 polyols.

The preparation method of described pirimiphos-methyl microcapsule insecticide, concrete steps are as follows:

Step 1, TDI (toluene-2,4-diisocyanate) trimer is dissolved in butyl acetate to obtain TDI (toluene-2,4-diisocyanate) trimer solution, pyrimiphos-methyl and TDI (toluene- Mix 2,4-diisocyanate) trimer solutions, let stand for half an hour, mix evenly to form an oil phase, add the emulsifier to deionized water, stir at a low speed to disperse, form a water phase, and pour the oil phase into the water phase High-speed stirring for emulsification to obtain a stable emulsion with uniform particle size;

Step 2, transfer the stable emulsion to a three-necked flask equipped with a stirring and heating device for stirring, slowly add the chain extender dropwise to the stable emulsion for interfacial polymerization reaction, and after the addition of the chain extender is completed, heat the stable emulsion solidified to obtain a microcapsule suspension;

Step 3, the microcapsule suspension is slowly lowered to room temperature, centrifuged with a centrifuge, the resulting precipitate is washed 3-5 times with deionized water, and dried at room temperature for 24-30 hours to obtain white microcapsule powder .

As a further scheme of the present invention: the mass fraction of TDI (toluene-2,4-diisocyanate) trimer in the TDI (toluene-2,4-diisocyanate) trimer solution is 50%.

As a further solution of the present invention: the stirring speed of the oil phase and the water phase in step 1 is 4000-6000 rpm.

As a further solution of the present invention: in step 2, the reaction temperature for the interfacial polymerization reaction between the chain extender and the stable emulsion is 40-60 degrees Celsius, and the reaction time is 2-4 hours.

Compared with the prior art, the beneficial effects of the present invention are: the surface of the microcapsules prepared by the present invention is compact and uniform, overcomes the shortcoming that pirimiphos-methyl is easy to volatilize, protects the active ingredient of pirimiphos-methyl, and regulates the microcapsules The core-wall ratio can control the release rate of pirimiphos-methyl; the invention improves the use efficiency of pirimiphos-methyl, reduces waste of resources and environmental pollution, and uses TDI trimer as the oil phase monomer to solve the problem of polyurethane micro- The disadvantage of high volatility of diisocyanate monomers in the capsule preparation process reduces the harm of chemical reagents to the human body during production, and overcomes the presence of formaldehyde in the capsule wall, cumbersome operation procedures, long preparation process, and greater harm to the environment and human health and other issues to meet people's needs.

Description of drawings

Fig. 1 is the scanning electron micrograph of the microcapsules when magnified 1000 times in Example 1 of the pirimiphos-methyl microcapsule insecticide.

Fig. 2 is the release curve of pirimiphos-methyl microcapsules with different core-to-wall ratios in the alcohol-water mixture of Examples 1-4 in the pirimiphos-methyl microcapsule insecticide.

Detailed ways

The technical solution of this patent will be further described in detail below in conjunction with specific embodiments.

Example 1

(1) Preparation of emulsion

Pour 15g of pyrimiphos-methyl into 30g of TDI trimer solution, let it stand for half an hour, mix well to form an oil phase; add 5g of SMA to deionized water, stir at a low speed to form a water phase; pour the oil phase into water The emulsification is carried out in the phase, the emulsifier speed is 6000 rpm, the emulsification time is 5min, and a stable emulsion with uniform particle size is obtained.

(2) Preparation of microcapsule suspension

Transfer the stable emulsion obtained by emulsification to a three-necked flask equipped with a stirring and heating device for stirring; slowly add 5g of 1,4-butanediol into the emulsion, and after the addition of 1,4-butanediol is completed, put The temperature of the emulsion was raised to 60 degrees Celsius, and the heat preservation was solidified for 2 hours to obtain a suspension of microcapsules.

(3) Preparation of microcapsule powder

The microcapsule suspension was slowly lowered to room temperature, centrifuged at a rate of 8000 rpm, the obtained precipitate was washed 3 times with deionized water, and dried at room temperature for 24 hours to obtain white microcapsule powder. The release profile of this microcapsule is shown in Fig. 2D.

Example 2

(1) Preparation of emulsion

Pour 15g of pyrimiphos-methyl into 24g of TDI trimer solution, let it stand for half an hour, mix well to form an oil phase; add 5g of SMA to deionized water, stir at a low speed to form a water phase; pour the oil phase into water The emulsification is carried out in the phase, the emulsifier speed is 6000 rpm, the emulsification time is 5min, and a stable emulsion with uniform particle size is obtained.

(2) Preparation of microcapsule suspension

Transfer the stable emulsion obtained by emulsification to a three-necked flask equipped with a stirring and heating device for stirring; slowly add 5g of 1,4-butanediol into the emulsion, and after the addition of 1,4-butanediol is completed, put The temperature of the emulsion was raised to 60 degrees Celsius, and the heat preservation was solidified for 2 hours to obtain a suspension of microcapsules.

(3) Preparation of microcapsule powder

The microcapsule suspension was slowly lowered to room temperature, centrifuged at a rate of 8000 rpm, the obtained precipitate was washed 3 times with deionized water, and dried at room temperature for 24 hours to obtain white microcapsule powder. The release profile of this microcapsule is shown in Figure 2C.

Example 3

(1) Preparation of emulsion

Pour 15g of pyrimiphos-methyl into 18g of TDI trimer solution, let it stand for half an hour, mix well to form an oil phase; add 5g of SMA to deionized water, stir at a low speed to form a water phase; pour the oil phase into water The emulsification is carried out in the phase, the emulsifier speed is 6000 rpm, the emulsification time is 5min, and a stable emulsion with uniform particle size is obtained.

(2) Preparation of microcapsule suspension

The stable emulsion obtained by emulsification is transferred to a three-necked flask equipped with a stirring and heating device for stirring; 15g polyethylene glycol 400 is slowly added dropwise to the emulsion, and after the addition of the polyethylene glycol 400 is completed, the emulsion is warmed up to 60 degrees Celsius, heat preservation and solidification for 2 hours to obtain a microcapsule suspension.

(3) Preparation of microcapsule powder

The microcapsule suspension was slowly lowered to room temperature, centrifuged at a rate of 8000 rpm, the obtained precipitate was washed 3 times with deionized water, and dried at room temperature for 24 hours to obtain white microcapsule powder. The release profile of this microcapsule is shown in Figure 2B.

Example 4

(1) Preparation of emulsion

Pour 15g of pyrimiphos-methyl into 12g of TDI trimer solution, let it stand for half an hour, mix well to form an oil phase; add 5g of SMA to deionized water, stir at a low speed to form a water phase; pour the oil phase into water The emulsification is carried out in the phase, the emulsifier speed is 6000 rpm, the emulsification time is 5min, and a stable emulsion with uniform particle size is obtained.

(2) Preparation of microcapsule suspension

The stable emulsion obtained by emulsification is transferred to a three-necked flask equipped with a stirring and heating device for stirring; 15g polyethylene glycol 600 is slowly added dropwise to the emulsion, and after the addition of the polyethylene glycol 600 is completed, the emulsion is warmed up to 60 degrees Celsius, heat preservation and solidification for 2 hours to obtain a microcapsule suspension.

(3) Preparation of microcapsule powder

The microcapsule suspension was slowly lowered to room temperature, centrifuged at a rate of 8000 rpm, the obtained precipitate was washed 3 times with deionized water, and dried at room temperature for 24 hours to obtain white microcapsule powder. The release profile of this microcapsule is shown in Figure 2A.

The drug loading of microcapsules can be regulated by the ratio of core to wall. There is no report on the preparation of pirimiphos-methyl microcapsules of polyurethane wall materials with TDI trimer as the oil phase monomer. The operation procedures are cumbersome, the preparation process takes a long time, and it is harmful to the environment and human health. It can effectively prevent the volatilization and degradation of active ingredients, and has the function of continuous and slow release.

It will be apparent to those skilled in the art that the invention is not limited to the details of the above-described exemplary embodiments, but that the invention can be embodied in other specific forms without departing from the spirit or essential characteristics of the invention. Accordingly, the embodiments should be regarded in all points of view as exemplary and not restrictive, the scope of the invention being defined by the appended claims rather than the foregoing description, and it is therefore intended that the scope of the invention be defined by the appended claims rather than by the foregoing description. All changes within the meaning and range of equivalents of the elements are embraced in the present invention. Any reference sign in a claim should not be construed as limiting the claim concerned.

In addition, it should be understood that although this specification is described according to implementation modes, not each implementation mode only contains an independent technical solution, and this description in the specification is only for clarity, and those skilled in the art should take the specification as a whole , the technical solutions in the various embodiments can also be properly combined to form other implementations that can be understood by those skilled in the art.

Claims (7)

1. a kind of pirimiphos-methyl microcapsule pesticide, it is characterised in that include the raw material of following parts by weight：Pirimiphos-methyl 90-100 parts, TDI (Toluene-2,4-diisocyanate, 4- diisocyanate) 40-100 parts of tripolymer, 30-100 parts of chain extender, 30-50 parts of emulsifying agent With 1000-1100 parts of deionized water.

2. pirimiphos-methyl microcapsule pesticide according to claim 1, it is characterised in that the emulsifying agent uses quality Fraction is 20% styrene maleic anhydride copolymer (SMA) aqueous solution.

3. pirimiphos-methyl microcapsule pesticide according to claim 1, it is characterised in that the chain extender using Isosorbide-5-Nitrae- At least one of butanediol, polyethylene glycol 400, Macrogol 600 polyalcohols.

A kind of 4. preparation method of pirimiphos-methyl microcapsule pesticide as described in claim 1-3 is any, it is characterised in that Comprise the following steps that：

Step 1, TDI (Toluene-2,4-diisocyanate, 4- diisocyanate) tripolymer is dissolved in butyl acetate and obtains TDI (Toluene-2,4-diisocyanate, 4- bis- Isocyanates) trimerization liquid solution, pirimiphos-methyl and the mixing of TDI (Toluene-2,4-diisocyanate, 4- diisocyanate) trimerization liquid solution, stand half H, is uniformly mixed and forms oil phase, emulsifying agent is added in deionized water, and stirring at low speed is disperseed, and water phase is formed, by oil phase Pour into the stirring of water phase high speed to be emulsified, obtain the stable emulsion of uniform particle sizes；

Step 2, stable emulsion is transferred in the three-necked flask equipped with stirring and heating unit and is stirred, chain extender is delayed Slow be added dropwise in stable emulsion carries out interface polymerization reaction, and after chain extender is added dropwise, stable emulsion elevated cure obtains Microcapsule suspensions；

Microcapsule suspensions are slowly dropped to room temperature, are centrifuged with centrifuge by step 3, by gained sediment spend from Sub- water washing 3-5 times, is dried at room temperature for 24-30h, you can obtains the microscapsule powder of white.

5. the preparation method of pirimiphos-methyl microcapsule pesticide according to claim 4, it is characterised in that the TDI The mass fraction of TDI (Toluene-2,4-diisocyanate, 4- diisocyanate) tripolymer is in (Toluene-2,4-diisocyanate, 4- diisocyanate) trimerization liquid solution 50%.

6. the preparation method of pirimiphos-methyl microcapsule pesticide according to claim 4, it is characterised in that the step Oil phase and the speed of agitator of water phase are 4000-6000 revs/min in one.

7. the preparation method of pirimiphos-methyl microcapsule pesticide according to claim 4, it is characterised in that the step The reaction temperature that chain extender carries out interface polymerization reaction with stable emulsion in two is 40-60 degrees Celsius, reaction time 2-4h.