The influence of repulping on the properties of polybutylene succinate-coated paper

Abstract

Environmentally friendly packaging is currently gaining more attention. Polybutylene succinate (PBS) is one of the bioplastics typically used as a coating color for paper packaging with an aim to increase water resistance. PBS-coated paper can usually be degraded by landfilling. However, management of paper waste from converting processes, overproduced packaging, and post-consumer packaging waste by using the recycling process is still challenging. Due to adhesion between PBS layer and fibers, separation of PBS layer from paper is quite difficult. This research aimed to study the properties of fibers and papers recycled from PBS-coated paper and compared the results with those from the uncoated one. Both papers were repulped using varying repulping times. It was found that PBS layer can be separated from fibers just by repulping; however, some PBS remained attached to the pulp. The recycled pulp was then formed into handsheets for paper testing. The results indicated that the handsheets prepared from recycled PBS-coated paper provided better tensile strength, burst strength and tear resistance as compared to handsheets made from recycled uncoated paper. This might be because the small fragments of PBS which remained attached to the pulp after the repulping process may melt and act as an adhesive during the drying process of handsheet making. It was also discovered that longer repulping time was beneficial since paper strength tended to increase. Thus, this research showed that recycling of PBS-coated paper can be done just by repulping under optimal conditions.