The pesticide produced in the factory is called technical medicine before it is processed into shape. The solid technical substance is called raw powder, and the liquid technical substance is called crude oil. The vast majority of pesticides are oil-soluble and cannot be used directly in agriculture. In order to spray a small amount of pesticides evenly on a large area of crops, one of the most commonly used methods is to formulate the original drug into an emulsifiable concentrate before use. EC is one of the basic formulations of pesticides. It is a transparent oily body prepared from pesticide technical drugs, emulsifiers, solvents and co-solvents. Adding water can form a relatively stable emulsion, and the stability is required to be above 99.5%. EC can be divided into two types: O/W type and W/O type. The O/W type generally uses a higher hydrophilic emulsifier, and the W/O type generally uses a higher lipophilic emulsifier. Most pesticide ECs are O/W ECs.
The development of pesticide EC is closely related to the development of surfactants. Surfactant is the emulsifier in emulsifiable concentrate, which is an important component of pesticide emulsifiable concentrate. The early organic synthetic pesticide DDT used soap or sulfated (or sulfonated) castor oil as an emulsifier. The formulated emulsifiable concentrate had high viscosity, poor flow performance, poor emulsifying and dispersing performance, and a large amount of emulsifier. In the mid-1940s, ether-type nonionic surfactants, such as alkylphenol polyoxyethylene ether, benzyl biphenol polyoxyethylene ether, etc., have occupied a major position in pesticide emulsifiers, but there are also many shortcomings. In 1955, he discovered a mixed pesticide emulsifier compounded by oil-soluble calcium dodecylbenzene sulfonate and nonionic surfactant. This mixed emulsifier not only has a significantly reduced dosage, but also has good automatic emulsification and dispersion properties, and is suitable for a wide range of applications. As long as different types of nonionic surfactants with different degrees of polymerization are selected, they can be used to formulate various pesticide emulsifiable concentrates.
After the emulsifiable concentrate is diluted with water to form an emulsion, the crude oil is dispersed into small droplets, so it can be applied evenly on a large area. Because the emulsifier contains an emulsifier, the emulsifiable concentrate is easier to wet and adhere to crops, germs and insects, and The drug can easily penetrate into their body and can obtain a good control effect. Since the emulsion is less affected by wind and rain, the effect period is longer. When the surfactant emulsifiable concentrate is processed and diluted with water, the original drug will not fly like the powder and cause harm to the operator. The use of emulsifiable concentrate is also very convenient. After being diluted with water to form an emulsion, it can be sprayed with a sprayer or other tools.