In order to provide a concise and concise description of the problem, some parts of the content are still selected to help readers understand the significance of surfactants in the ultrafine grinding preparation of pesticide suspensions.
1. The viscosity increases during the grinding process.
The main reason is that dispersants are not easily deformed, do not adsorb firmly, and are prone to detachment from the surface of particles. There are substances with low melting points and high boiling points in the raw material. Additives with combined wetting and dispersion functions, especially three-dimensional structured polymer surfactants, can be used to improve adsorption fastness, adsorption layer thickness, increase inter particle lubrication, and increase the content of the original drug.
2. Foam is too much during grinding.
The main reason is that the dispersant was chosen incorrectly. Wetting dispersants with certain anti foaming functions can be used, with a small amount of anti foaming agent added. Excessive silicone defoamer can easily cause system instability and delamination of water.
3. The viscosity of the system is high after grinding.
The main reason is that the selection of auxiliary systems is basically correct, but dispersants with wetting and viscosity reducing effects need to be added. Wetting dispersants with good lipophilicity can be used to control the viscosity between 200-400mpa. s.
4. After grinding, the thermal storage pastes or the viscosity increases.
The main reasons are improper selection of antifreeze, anti settling, and wetting dispersant. High molecular surfactant can be used to achieve multi-point and multi-level adsorbent, reduce the area of "exposed" particles, select appropriate antifreeze, reduce the solubility of dispersant or particles in continuous phase, replace anti settling agent, reduce the possibility of induced crystallization, select high molecular surfactant, and reduce the solubility of crude drug in low molecular auxiliary.
Careful readers can find that the first two common problems in the grinding process of pesticide suspension agents are actually common problems encountered by other powder materials in wet grinding. Perhaps drawing on the experience of this field, there will be new solutions and breakthroughs!