Today, let's talk about several factors that affect the coating quality of coater.
The function of coater's coating blade is to measure and control the desired coating amount on the surface of the paper, and remove excessive coating. This process can improve and improve the smoothness and gloss of the coated paper surface.
In order to achieve the above goals, the first is the quality requirements of the coater blade. The working surface of the coating scraper must be free of crack defects, and it is necessary to ensure that there is uniform and the same anti friction performance (wear resistance) on the whole banner of the coating surface, so as to maintain the same quality of the coated paper surface after the coating process.
Secondly, the importance of feeding space: when the coating is applied by the scraper, 85-95% of the coating will return to the coating reserve system, so there is a sufficient space in this area to complete feeding and reflow.
Finally, how to avoid backflow: after the paper is coated by the scraper, the coating begins to dehydrate and solidify gradually - forming a "semi dehydrated coating area", where the coating gradually dehydrates along the forward direction of the base paper. When the coating is further dehydrated to form "pre coating" or "bread after filtering", the blade pressure of the blade will "transfer" the shape of the coated blade surface to the surface of the paper coating. In this process, the blade has the greatest pressure on the coating, so it is easy to form a thin coating behind the blade tip. Excessive pressure or poor paint rheology can cause backflow here. Therefore, it is necessary to adjust the cutter pressure reasonably according to the field situation to avoid backflow.
Coater coating process is a seemingly simple, in fact cumbersome process, need to do every step carefully to achieve perfect control.