Mineral oils, amides, low-grade alcohols, fatty acids and fatty acid esters, phosphates and other organic defoaming agents have been studied and applied earlier, belonging to the first generation of defoaming agents, which have the advantages of easy access to raw materials, high environmental performance and low production cost. The disadvantage is that the defoaming efficiency is low, the specificity is strong, the use condition is harsh.
Polyether defoaming agents are the second generation of defoaming agents, mainly including straight chain polyethers, alcohols or ammonia as the starting agent polyether, end group esterified polyether derivatives three kinds. The biggest advantage of polyether defoaming agent is its strong foaming inhibition ability. In addition, there are some polyether defoaming agents with high temperature resistance, strong acid and alkali resistance and other excellent properties; The disadvantage is that the use condition is limited by temperature, the use of narrow field, poor defoaming ability, low bubble breaking rate.
Silicone defoaming agents (the third generation of defoaming agents) have strong defoaming performance, rapid foaming ability, low volatility, no toxicity to the environment, no physiological inertia, wide range of use and other advantages, so it has a broad application prospect and huge market potential, but the foaming inhibition performance is poor.
Polyether modified polysiloxane defoaming agent has the advantages of polyether defoaming agent and organosilicon defoaming agent. It is the development direction of defoaming agent. Sometimes it can be reused according to its inverse solubility, but at present there are fewer types of such antifoaming agents, which are still in the research and development stage, and the cost of production is higher.