In the production process of paper trays, about 3.5-4.5KG of water is removed for every kilogram of bamboo pulp paper tray products after a boring process. Therefore, drying is an important process in the production of paper trays. The production cost of the drying process occupies a large proportion in the production of paper trays. Adding the drying power of paper trays is a key method for adding paper trays.
Open flat paper tray
The wet paper mold with paper fiber as the main component is a porous object with capillary structure inside. Moisture exists between the outer surface of the fiber and the pores of the fiber capillary. The paper support products used for the inner packaging of products generally require outstanding dynamic cushioning properties, and the moisture in it cannot be removed by mechanical exploitation, but needs to be removed by a boring method. Therefore, compared with the conventional paper drying process, the drying strength of the pulp molded product is very large. On the one hand, hot air serves as a heat source to provide energy for transpiration of moisture, and on the other hand, it acts as a moisture carrier to take away the moisture that is continuously transpired.
The moisture in the wet paper tray depends on the internal dispersion and external dispersion of the water. The so-called internal dispersion refers to the migration process of the water in the wet paper tray from the inside to the outside; the external dispersion refers to the moisture being carried away from the outside. The process of walking. The unevenness of the dryness rate of the paper support depends on the water function, the speed of the external dispersion and the balance and harmony between the two, and the reasonable process conditions should be drawn up around the above two aspects and the dry physical properties of the paper support product.
After the bamboo pulp paper support product is vacuum-adsorbed and molded, there are three ways for water to exist in the wet paper fibers: bound water, adsorbed water and free water. The purpose of paper tray products is to get rid of the free water in between, so that the bamboo pulp paper tray reaches the equilibrium moisture content.
The drying mechanism of paper tray is that when the water vapor pressure on the surface of the wet paper tray is greater than the partial pressure of water vapor in the dry medium, the moisture on the surface of the wet blank will continue to vaporize and enter the air, and the moisture in the wet blank will continue to disperse to its surface. The speed of vaporization and dispersion varies with the temperature of the medium, the moisture of the wet blank, the thickness and size of the paper support, and so on.
