A better Cobb value through PAC

One of the most important steps in paper production is surface sizing, because the hydrophobicity of the paper surface is crucial for the subsequent print image or even water resistance. In most cases, this key performance property of paper is adjusted exclusively with a surface sizing agent.

There are often problems with increased Cobb values occurring when using surface sizing , which can only be slightly improved with an additional dosage of surface sizing agent. A second  adjusting screw  would be desirable to solve this problem.

In order to improve sizing efficiency, we started a field trial. In this we used, at a leading manufacturer of packaging papers in addition to surface sizing as a hydrophobizing agent, Sachtoklar as a booster for sizing,.

The main objective here is to improve surface hydrophobicity by determining an optimum ratio of Sachtoklar and sizing agent in a practical trial. Sachtoklar helps the sizing agent to find its way to the fiber. This is an additional option, especially in hopeless situations, which is either overlooked or not even known.

In the execution of our experiment, the amount of surface size was not changed, only the ratio of Sachtoklar was adjusted.

The results show a clear improvement of the Cobb values with increasing dosage of Sachtoklar. A decrease in water penetration can be seen in the images. The Cobb values could be optimized by 25% by adjusting the amount of Sachtoklar. In principle, lower size quantities are also conceivable as a result, which could lead to cost savings.