阅读说明：本技术 一种pH敏感响应性幼果伤液控释农药制剂及其制备方法 (PH-sensitive responsive young fruit injury liquid controlled-release pesticide preparation and preparation method thereof ) 是由 张志祥 王瑞飞 闫超 王世英 马千里 郑烽 朱启绽 王勇庆 徐汉虹 黄长安 于 2019-10-30 设计创作，主要内容包括：本发明公开了一种pH敏感响应性幼果伤液控释农药制剂,由以下原料制得：壳聚糖、酸试剂、农药活性成分、交联剂溶液、羧甲基壳聚糖溶液和乳液。制备方法为：(1)称取各原料；(2)将壳聚糖加入酸试剂中溶解,然后加入农药活性成分混合；(3)加入交联剂溶液并搅拌反应；(4)在搅拌状态下加入羧甲基壳聚糖溶液,调pH,搅拌反应,离心分离,冷冻干燥,得到农药纳米颗粒；(5)加入乳液中混合均匀,即得。本发明农药制剂中的农药纳米微粒颗粒小,分散性高,具备优良的抗光解及酸性释放性能,且制备方法简单易行,重复性好。(The invention discloses a pH-sensitive responsive young fruit injury liquid controlled-release pesticide preparation which is prepared from the following raw materials: chitosan, acid reagents, pesticide active ingredients, cross-linker solutions, carboxymethyl chitosan solutions and emulsions. The preparation method comprises the following steps: (1) weighing the raw materials; (2) adding chitosan into an acid reagent for dissolving, and then adding and mixing pesticide active ingredients; (3) adding a cross-linking agent solution and stirring for reaction; (4) adding a carboxymethyl chitosan solution under stirring, adjusting the pH value, stirring for reaction, performing centrifugal separation, and performing freeze drying to obtain pesticide nanoparticles; (5) adding into the emulsion, and mixing. The pesticide nanoparticles in the pesticide preparation are small in particle size, high in dispersity, excellent in photolysis resistance and acid release performance, simple and easy to prepare, and good in repeatability.)

1. A pH-sensitive responsive young fruit injury liquid controlled-release pesticide preparation is characterized by comprising the following raw materials: chitosan, acid reagents, pesticide active ingredients, cross-linker solutions, carboxymethyl chitosan solutions and emulsions;

wherein the mass ratio of the chitosan, the acid reagent, the pesticide active ingredient, the cross-linking agent solution, the carboxymethyl chitosan aqueous solution and the emulsion is (2-6) 1000 (0.1-10) to (200-400) to (500-1000): (200-40000).

2. The pH-sensitive and responsive young fruit injury controlled-release pesticide preparation as claimed in claim 1, wherein the chitosan has a molecular weight of 7.5-1200 kDa.

3. The pH-sensitive and responsive young fruit injury controlled-release pesticide preparation as claimed in claim 1, wherein the acid reagent is an acid solution with a mass fraction of 1-2%;

the acid is acetic acid, hydrochloric acid or citric acid.

4. The pH-sensitive and responsive young fruit injury controlled-release pesticide preparation as claimed in claim 1, wherein the pesticide active ingredient is any one of abamectin, acetamiprid, imidacloprid, dinotefuran, nitenpyram, beta-cypermethrin, thiamethoxam, clothianidin and azadirachtin.

5. The pH-sensitive and responsive young fruit injury liquid controlled-release pesticide preparation as claimed in claim 1, wherein the cross-linking agent solution is a cross-linking agent aqueous solution with a mass fraction of 0.2-0.4%;

the cross-linking agent is any one of sodium tripolyphosphate, glutaraldehyde and glycerol.

6. The pH-sensitive and responsive young fruit injury liquid controlled-release pesticide preparation as claimed in claim 1, wherein the carboxymethyl chitosan solution is 0.3-0.5% by mass of carboxymethyl chitosan aqueous solution;

the carboxymethyl chitosan is O-carboxymethyl chitosan or N, O-carboxymethyl chitosan.

7. The pH-sensitive and responsive young fruit injury controlled-release pesticide preparation as claimed in claim 1, wherein the emulsion is 0.1-0.5% by weight of an aqueous solution of an emulsifier;

the emulsifier is any one of sodium dodecyl sulfate, calcium dodecyl benzene sulfonate and pesticide emulsifier 0201B.

8. A preparation method of a pH-sensitive responsive young fruit injury liquid controlled-release pesticide preparation is characterized by comprising the following steps:

(1) weighing the raw materials according to the pH-sensitive and responsive young fruit injury liquid controlled-release pesticide preparation of any one of claims 1 to 7;

(2) adding chitosan into an acid reagent for dissolving, and then adding pesticide active ingredients for uniformly mixing to obtain a mixed solution A;

(3) adding the cross-linking agent solution into the mixed solution A, mixing and stirring for reaction to obtain a mixed solution B;

(4) adding the carboxymethyl chitosan solution into the mixed solution B under the stirring state, then adjusting the pH value of the solution to 4-7, stirring until the reaction is complete, and performing centrifugal separation and freeze drying to obtain pesticide nanoparticles;

(5) and adding the pesticide nanoparticles into the emulsion and uniformly mixing to obtain the pH-sensitive responsive young fruit injury liquid controlled-release pesticide preparation.

9. The method for preparing a pH-sensitive and responsive young fruit injury liquid controlled-release pesticide preparation as claimed in claim 8, wherein in the step (3), the stirring speed is 200-1500 r/min and the stirring time is 30-120 min.

10. The method for preparing a pH-sensitive and responsive young fruit injury liquid controlled-release pesticide preparation as claimed in claim 8, wherein in the step (4), the stirring speed is 200-500 r/min, and the time is 180-240 min;

the rotating speed of the centrifugal separation is 14000-16000 r/min, and the time is 20-40 min.

Technical Field

The invention relates to the technical field of pesticides, in particular to a pH-sensitive and responsive young fruit injury liquid controlled-release pesticide preparation and a preparation method thereof.

Background

Fruits and vegetables are increasingly popular among people in the adjustment of dietary structures in the modern times, and due to the health value and the mouthfeel of the fruits and the vegetables, the proportion of the fruits and the vegetables in the dietary structures of people is also greatly increased. Fruits and vegetables are very easy to be infected by diseases and insects in the young fruit period, the protection of the fruits and vegetables in the young fruit period is mainly bag covering or spraying pesticide application, however, the bag covering process of the fruits and vegetables is very complicated, the fruits need to be bundled one by one in the bag covering process, and great manpower is consumed; although the pesticide is used for spraying fruits and vegetables, the problem of pest control can be solved, the traditional dosage forms have different losses in the pesticide application process, such as the losses of pesticide liquid drops such as drifting, slipping and dust drifting, after the pesticide is applied, only less than 30 percent of pesticide can be attached to the surface of the target crop, on the basis, the pesticide reaching the pest body is not enough for 0.1 percent of the application amount, the pesticide effect utilization rate of the existing pesticide application mode is lower, meanwhile, the problems that the lasting period of the pesticide on the target crops cannot coincide with the period of the pest damage, the pesticide is easy to oxidize and decompose, the residual period is short and the like cause the reduction of the utilization rate of the pesticide, most farmers prevent and control the plant diseases and insect pests on the fruits and vegetables by means of multiple pesticide spraying and dosage increasing, the incorrect pesticide application mode not only increases the risk of pesticide residue, but also wastes a great amount of manpower and material resources.

Researches show that pests on fruits and vegetables such as bactrocera dorsalis and drosophila melanogaster and the like have habits of tending to hurt and directionally laying eggs, for example, the guava is rich in a large amount of folic acid, tannin, acetic acid leaf alcohol ester, ethyl acetate, acetic acid hexyl ester and the like in fruits in the young fruit period, the fruits are acidic in the young fruit period, wind and rain injury, insect injury and mechanical scratch can cause the fruits to have wounds, wound fluid flows out of the wounds, and the wound fluid of the young fruits of the fruits is acidic.

Therefore, how to develop a pesticide preparation with sensitive response to pH to improve the pesticide utilization rate is a problem to be solved urgently by those skilled in the art.

Disclosure of Invention

In view of the above, the invention provides a pH-sensitive responsive young fruit injury liquid controlled-release pesticide preparation and a preparation method thereof, the preparation can release insecticidal active ingredients under an acidic condition to solve the technical problem of low utilization rate of the existing pesticide, the prepared pesticide preparation has small pesticide nanoparticle particles, high dispersibility, excellent photolysis resistance and acid release performance, and the preparation method is simple and easy to implement and has good repeatability.

In order to achieve the purpose, the invention adopts the following technical scheme:

a pH-sensitive responsive young fruit injury liquid controlled-release pesticide preparation is characterized by being prepared from the following raw materials: chitosan, acid reagents, pesticide active ingredients, cross-linker solutions, carboxymethyl chitosan solutions and emulsions;

the mass ratio of the chitosan, the acid reagent, the pesticide active ingredient, the cross-linking agent solution, the carboxymethyl chitosan aqueous solution and the emulsion is (2-6) 1000 (0.1-10) 200-400 (500-1000): (200-40000).

Furthermore, the molecular weight of the chitosan is 7.5-1200 kDa, and the deacetylation degree is more than 90%.

The chitosan is the only natural cationic biological polysaccharide in the nature, has large storage capacity in the nature, is natural and degradable, and has the characteristics of certain biocompatibility, safety, no toxicity, no pollution to the environment and the like.

Further, the acid reagent is an acid solution with the mass fraction of 1-2%;

further, the acid is acetic acid, hydrochloric acid or citric acid.

The further beneficial effect of the above is that the acid agent of the present invention can dissolve the chitosan solution more fully.

Further, the pesticide active ingredient is any one of abamectin, acetamiprid, imidacloprid, dinotefuran, nitenpyram, beta-cypermethrin, thiamethoxam, clothianidin and azadirachtin.

The pesticide has the advantages that the pesticide active ingredient has strong permeability, can be quickly absorbed by crops after being used, and can effectively protect the crops from being damaged; meanwhile, the composition has strong activity of killing the larvae which are hatched initially, so that the survival rate of pests is greatly reduced; the drug effect is very durable, and the drug effect cannot be lost even in rainy days.

Further, the cross-linking agent solution is a cross-linking agent water solution with the mass fraction of 0.2-0.4%;

further, the crosslinking agent is any one of sodium tripolyphosphate, glutaraldehyde and glycerol.

The method has the further beneficial effects that the pesticide nano-particles are prepared by adding the small molecular cross-linking agent with negative charges and the chitosan solution with positive charges and utilizing the electrostatic action, and the method is simple and convenient to operate and low in cost.

Further, the carboxymethyl chitosan solution accounts for 0.3 to 0.5 mass percent of the carboxymethyl chitosan aqueous solution;

furthermore, the carboxymethyl chitosan is O-carboxymethyl chitosan or N, O-carboxymethyl chitosan, and the substitution degree of carboxymethyl is more than 80%.

The further beneficial effects of the adoption are that the carboxymethyl chitosan has better water solubility than chitosan as a derivative of the chitosan, has a certain bacteriostatic action and excellent biocompatibility, and can chelate calcium ions in plant cells through carboxymethyl groups so as to open intercellular tight connection.

Further, the emulsion is an emulsifier aqueous solution with the mass fraction of 0.1-0.5%;

further, the emulsifier is any one of sodium lauryl sulfate, calcium dodecylbenzenesulfonate, and a pesticide emulsifier 0201B.

The emulsifier has the further beneficial effects that the adhesive force of the pesticide nano-particles on the surfaces of crops can be improved, and the effective utilization rate of the preparation is improved.

The invention also provides a preparation method of the pH-sensitive responsive young fruit injury liquid controlled-release pesticide preparation, which specifically comprises the following steps:

(1) weighing the raw materials according to the mass of the pH sensitive responsive young fruit injury liquid controlled-release pesticide preparation;

(2) adding chitosan into an acid reagent for dissolving, and then adding pesticide active ingredients for mixing to obtain a mixed solution A;

(3) adding the cross-linking agent solution into the mixed solution A obtained in the step (2), mixing, and stirring at the rotating speed of 200-1500 r/min for reaction for 30-120 min to obtain a mixed solution B;

(4) adding a carboxymethyl chitosan solution into the mixed solution B obtained in the step (3) under a stirring state, then adjusting the pH value of the solution to 4-7, stirring and reacting for 180-240 min at a rotating speed of 200-500 r/min, then performing centrifugal separation for 20-40 min at a rotating speed of 14000-16000 r/min, and freeze-drying for 12h to obtain pesticide nanoparticles;

(5) and (4) adding the pesticide nanoparticles obtained in the step (4) into the emulsion, and uniformly mixing to obtain the pH-sensitive responsive young fruit injury liquid controlled-release pesticide preparation.

According to the technical scheme, compared with the prior art, the invention has the beneficial effects that:

1. the pH-sensitive and responsive young fruit injury liquid controlled-release pesticide preparation is prepared by a three-step method (pre-configuration, ionic crosslinking and polymer agglomeration), the amino on a molecular group is utilized to endow the system with acid sensitivity, and meanwhile, the pesticide is released at different rates by controlling the number of the amino according to the difference of the environmental pH, the more the number of the amino is, the stronger the pH response effect of the acidic environment is, the preparation method is simple and easy to operate, the synthesis period is short, the materials are easy to obtain, the carrier material and the pesticide active ingredient can generate a synergistic effect, the redundant materials do not need to be removed, and a novel thought is provided for the research and development of a new pesticide formulation;

2. the invention adopts chitosan and carboxymethyl chitosan as pesticide carriers, and the prepared pesticide preparation has the characteristics of great release under acidic conditions and slow release under other conditions, can be activated under the acidic environment of young fruit wound liquid, regularly and fixedly releases insecticidal active substances aiming at the wound habit of pests, synchronizes the action period of the pesticide and the damage period of the pests, greatly increases the effective utilization rate of the pesticide, and solves the problem of short residual period of the pesticide, thereby achieving the purposes of efficient and intelligent application of the pesticide, saving time and labor and finally achieving the purposes of one-time pesticide application and multiple prevention and cure.

Drawings

Fig. 1 is a scanning electron microscope image of a pH-sensitive responsive young fruit injury liquid-controlled release pesticide preparation prepared in example 1 of the present invention;

FIG. 2 is a graph showing a distribution of particle sizes of pH-sensitive and responsive liquid-controlled release pesticide formulations for young fruit wounds, prepared in example 1 of the present invention;

fig. 3 is a release profile of the pH sensitive and responsive young fruit injury controlled-release pesticide formulation prepared in example 1 of the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention are clearly and completely described below, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.