Study on Water Content of Corrugated Cardboard

The so-called corrugated board moisture content, refers to the water content in the corrugated board (usually expressed as a percentage). The paper material that constitutes the paperboard is, from the microscopic structure point of view, a myriad of diamond-shaped structures formed by the interweaving of fully dispersed fibers. The arrangement and stacking of these diamond-shaped structures are directional and random, and thus inevitably form some Pores, resulting in a non-compact porous structure of the paper, easily contain moisture and have hydrophilicity.

In addition, the role of many hydroxyl groups (-0H) and fiber capillaries on cellulose macromolecules enables the paper to absorb and dehumidify moisture, that is, when the ambient humidity is high and the moisture content in the atmosphere is greater than the moisture content of the paper, the paper The material absorbs moisture from the nearby atmosphere until the moisture content of the two reaches equilibrium;

On the other hand, when the ambient humidity is low, the moisture content in the atmosphere is less than the moisture content of the paper. The paper material releases a portion of water, which balances the water content with the nearby atmospheric moisture content. When the paper material absorbs moisture, the water molecules slowly permeate and seep into the fibers, and the fibers that are tightened with each other are dispersed. The hydrogen bonds that have been formed between the fiber molecules are affected by the participation of the water molecules, and as a result, the binding between the fiber molecules is achieved. Changes have a direct impact on the strength of the cardboard.

If the paper sheet reaches a certain humidity from high humidity to low humidity, or if the humidity is reached from low humidity to high humidity, the former will have a moisture content greater than the latter, which is called "hysteresis". Hygroscopicity is easy to let wet. To eliminate this effect, the former must deal with a humidity condition that is still dry before the humidity, and then humidify to the humidity condition before it is consistent with the moisture content of the latter.