Knowledge of Pesticide Adjuvants

Aug 19, 2021

Each pesticide adjuvant has a specific function: some can dilute the original drug; some can help the original drug to be evenly dispersed in the preparation; some can prevent the droplets from agglomerating and becoming larger; some can increase the wetting of the particles Sex, adhesion or permeability; some can prevent the decomposition of active ingredients; some can increase the safety of application, and so on. In short, the function of pesticide adjuvants is nothing more than improving the physical or chemical properties of pesticides, maximizing efficacy or contributing to safe application. Pesticide additives are developed with the advancement of formulation processing and application technology. Early inorganic pesticides rarely used adjuvants. Since the development of organic pesticides, various additives have also been developed. With the diversification of dosage forms and the improvement of performance, the adjuvants have also developed into multiple varieties and series to meet the needs of different types of pesticides and different dosage forms, and special formulation processing technologies have emerged.

Commonly used additives include the following categories: 
Fillers and Carriers "Inert solid fillers used to dilute the original drug in dosage form processing are called fillers; fillers that can absorb or carry effective ingredients are called carriers. The filler not only dilutes, but also improves the physical properties, which is beneficial to the pulverization and dispersion of the original drug. The physical and chemical properties of the filler are related to the stability of the formulation and should be selected for use. Powder processing mostly uses neutral inorganic minerals such as pottery clay, kaolin (see clay), diatomaceous earth, talc and so on. The impregnation method granules use activated clay and bentonite (see clay) with strong oil absorption. Coating granules use non-oil-absorbing granular silica sand as the carrier.
Emulsifier "a type of surface active agent, which can make a kind of fluid be stably dispersed in another immiscible liquid (such as oil in water) with tiny droplets to form an emulsion. Commonly used are nonionic surfactants such as polyoxyethylene esters and ethers, and anionic surfactants such as alkylbenzene sulfonates. Generally, non-ionic and anionic emulsifiers are used, and the ratio is adjusted to the most appropriate hydrophilic-lipophilic balance (HLB value) to obtain the best emulsification effect.
Dispersant" is a type of surfactant whose function is to keep the powder dispersed and prevent agglomeration. Commonly used are alkyl aryl sulfonate and its formaldehyde condensate, lignin sulfonate, alkylphenol polyoxyethylene ether formaldehyde condensate, sulfate and so on.
Wetting agent is a type of surfactant whose function is to reduce the surface tension of the drug solution, so that the drug particles can be wetted quickly, and the drug solution can be easily wetted and spread on the surface of the application target to help the drug penetrate. Commonly used are saponin-containing saponin powder, tea seed cake powder and lignin-containing sulfite pulp waste liquid, as well as synthetic surfactants such as polyoxyethylene alkyl aryl ether and polyoxyethylene alkyl ether , Alkylbenzene sulfonate, alkyl naphthalene sulfonate, etc.

"Spreading agent" is a type of surfactant whose function is to enhance the fixation ability of the drug on the application target surface, resist wind and rain washing, make the medicinal effect fully play, and have both wet spreading and penetrating capabilities. Commonly used are nonionic or anionic surfactants, lignosulfonates, and casein. In some cases, adding some mineral oil or vegetable oil to the liquid medicine can also play a role.
Solvent refers to the general term for solvents, liquid diluents and/or carriers used in the industrial production and application of pesticides. Such as benzene, diesel, methanol, petroleum ether, etc.
Adhesive agent can increase the adhesion of pesticides to solid surfaces. Additives that can increase the adhesion of pesticides to solid surfaces. It can improve the resistance to rain washing and improve the durability. Such as mineral oil, gelatin, polyvinyl alcohol, etc.
Stabilizer refers to the general term for various additives that delay and prevent the spontaneous deterioration of the chemical and physical properties of pesticides and processed products. Stabilizers have two functions: one is to maintain and enhance the physical and physical and chemical properties of the product, including anti-crystallization, anti-flocculation, sedimentation, anti-caking and suspension additives, etc., called physical stabilizers; the other is chemical stability Agents, including anti-decomposition, anti-oxidation, anti-ultraviolet radiation, etc., they mainly maintain and enhance the chemical properties of the product, especially to prevent and slow down the decomposition of active ingredients. Such as 1,2-butanediol, isopropyl phosphate, wgwin D902 (used to inhibit the decomposition of emamectin benzoate and abamectin) and so on.

Spray Auxiliaries Refers to the general name of the additives used in spray application. The reason for the application of spray additives is that the current pesticide application technology, especially the spray application technology, generally has the problem of low effective utilization rate of pesticides. Someone conducted a typical investigation on the distribution of pesticides after spraying in the field, and pointed out that the pesticide dose that actually reaches the pest body is less than 1% of the pesticide dose, that is, more than 99% of the pesticide not only has no effect, but becomes The source of pollution has attracted more and more attention. Today, spray additives have become a very active field in the field of additives in the United States, Japan, and Western Europe. In the United States, adjuvants are almost always used when spraying herbicides, and this is the case for both high-efficiency and super-effective herbicides.