Common defoamers（I）

In the process of industrial production, a lot of harmful bubbles will be generated, and defoamer should be added. There are many kinds of defoamers, such as organosiloxane, polyether, grafting of silicon and ether, containing amines, imines and amides, which have the characteristics of faster defoaming speed, longer foam inhibition time, wider applicable medium range, and even harsh medium environment such as high temperature, strong acid and strong base. It is widely used to remove harmful foam produced in latex, textile sizing, food fermentation, biological medicine, coating, petrochemical, paper making, industrial cleaning and other industries.


1. Natural oil (i.e. soybean oil, corn oil, etc.)


Advantages: easy source, low price, easy to use;


Disadvantages: if the storage is not good, it is easy to deteriorate and increase the acid value.






2. High carbon alcohol


High carbon alcohol is a strong hydrophobic and weak hydrophilic linear molecule, which is an effective defoamer in water system. In the early 1970s, Soviet Union scholars experimented in the aqueous solution of anionic, cationic and non-ionic surfactants, and proposed that the defoaming effect of alcohol was related to its solubility and diffusion degree in the foaming solution. C7 ~ C9 alcohol is the most effective defoamer.


The high alcohols of C12~C22 are made up of suitable emulsifiers, which are made up of water emulsions with a particle size of 4~9 m and 20~50% content, that is, the defoamer of water system.


Some esters, such as phenylethanol oleate and lauryl phenylacetate, have antifoaming effects in penicillin fermentation, and the latter can also be used as a precursor.