Eco-friendly materials become more important for the sustainable economy. The great increase in the demand of the eco-friendly materials especially for the packaging industry lead to great interest in the pulp mold which made with wood pulp or recycled paper. Since the wet pulp mold provide not only biodegradable packaging but also various properties such as impact absorbing, the wet pulp mold could be one of promising alternative to polymer packaging material. In this study, the systematic study about the process and the properties of the wet pulp mold was conducted for providing various application of the wet pulp mold by increasing the properties of the wet pulp mold efficiently.
This study was conducted to proceed with the process research and functionalization research of wet pulp mold. In order to understand the effect of the wet pulp mold process conditions, a laboratory wet pulp mold pilot molding machine was applied, and the study on the influence of the wet pulp mold by raw materials was conducted. The moisture absorption and the moisture resistance of the wet pulp mold were also evaluated based on those studies.
The effects of process conditions of wet pulp mold manufacturing on the properties of the pulp mold were investigated with a pilot wet pulp mold simulator. The stock concentration, the vacuum forming pressure, the vacuum forming time, the couching condition and mesh hole size were controlled for this experiment. The higher stock concentration, the higher vacuum forming pressure and the longer vacuum forming time resulted in the higher grammage of pulp mold samples. The mesh hole size had influence on the pulp mold bulk was and the smaller hole size of the mesh resulted in the higher bulk of the pulp mold. The couching process caused the high dryness after forming. The pulp mold made from low-consistency stock had the higher drying speed compared to the high-consistency stock.

The applicability of the lignocellulosic biomass resources to the wet pulp mold was evaluated for developing new utilization of coniferous fallen leaves, citrus pomace, and rice husk fiber. The wet pulp mold with fallen leaves showed higher strength properties than the wet pulp mold with fresh leaves. The scent of the wet pulp mold with fresh leaves was stronger than fallen leaves. The higher addition of the fiber fraction of the citrus pomace resulted in the lower bulk and drying efficiency of the pulp mold samples because of the irregular size distribution. The surface treatment of the citrus pomace fine fraction on the pulp mold would show the endowment of the functional properties such as the citrus scent and color.
The various approach such as the low polarity solvent forming, the double-layered structure, the natural water absorption additives, and surface embossing treatment were developed for providing bulkier structure following higher water absorption of wet pulp mold. The higher contents of the low polarity solvent in the forming solution resulted in the bulkier structure, a faster drying speed, and higher water absorption properties. The double-layered wet pulp mold samples and the addition of natural water absorption additives such as glucomannan and carboxyl methylcellulose (CMC) increased the water absorption amount. At the proper conditions of moisture contents and suction pressure, and the size of the suction inlet, the surface embossing treatment provided the bulkier structure which led to the increase in the cushioning property and the higher water absorption amount.
The additions agents and surface coating were developed for providing water resistance absorption on wet pulp mold. The addition of oil palm EFB fiber showed an improvement in the water-resistance of the pulp mold. The effects of various additives on the improvement in the water resistance properties of the pulp mold were tested by using AKD, PVAm, epoxy resin. The application of AKD led to a higher increase in water resistance. The surface treatments with PVA and AKD on the wet pulp mold showed a significant reduction in the water absorption rate.
The effects of the process and the raw material on the wet pulp mold were deeply evaluated in this study. The functional properties were endowed to the wet pulp mold by changing the processes and the raw materials. The wide application of the wet pulp mold could be possible by upgrading the structural and the functional properties of the wet pulp mold based on this study.