The foam in the papermaking process is formed partly because of the added auxiliary additives, such as the added sizing agent and wet strength agent, similar to this surfactant containing foaming medium, it is easy to cause the production of a large number of bubbles. In addition, it may be because the paper slurry is not washed clean, which is mixed with air, resulting in the formation of foam. In the past, faced with the problem of papermaking foam, due to the relatively backward technology, it is generally the use of relatively backward mechanical methods, or the use of artificial foam removal. And now, there is a more effective and convenient defoaming method, that is, the use of paper defoaming agents.

Action principle of defoamer

Bubble Burst:

① Spreading: reduce the surface tension of the liquid film on the surface of the foam;

② Embedding: the formation of local weak points, so that the bubble burst. Foam suppression: Inhibit the formation of foam.

The formation and bursting of foam is a dynamic process, after the foam is broken, improper stirring will lead to the production of foam again, so a good defoamer should have the function of breaking and suppressing bubbles at the same time.

Precautions for the use of defoamer

First, the general dosage in the paper industry is 0.01 ~ 0.03%;

Second, in the use of defoamer, even if not stratified, before use should also be properly stirred, if stratified, it is recommended not to use, if you want to use, before use must be fully stirred and mixed;

Third, generally do not need to dilute, can be directly added. If diluted, it is best to use with dilution.

Fourth, to master the performance of defoamer and defoamer duration;

Fifth, according to the addition of different parts, slurry and white water flow changes, the amount of defoamer is also changed at any time, and in order to better disperse in the medium, the addition point should be far from the foam generation location;

6. The efficiency of using more than two kinds of defoamer at the same time is higher than that of a single defoamer, but note that the adding points of different defoamer should be far away;

Seven, according to different sections to choose different defoamer.