A new potential paper resource; recyclability of paper cups coated with water-soluble polyacrylate-based polymer

摘要

Paper cups are typically made by laminating PE or PLA onto the surface of paper. PE and PLA are hydrophobic and easy for film formation. However, recycling of PE- or PLA-coated paper cups is difficult. Polyacrylate (PA)-based polymers may be an alternative to PE and PLA, and recycling of polyacrylate-coated paper cups may be considered if the barrier film can be disintegrated. The recyclability of paper cups coated with PE-, PLA-, and PA-based polymers was investigated by pilot pulper and screen. Furthermore, mechanical treatments were investigated for the removal of remaining polyacrylate flakes (RPF). The pulping yield of PA-coated paper cups was higher than that of PE-or PLA-coated paper cups, since PE or PLA films were discarded as hole screen rejects. In the case of PA-coated paper cups, RPF could not be separated by slot screening due to its deformability. However, RPF must be treated properly since it can result in specks on the surface of paper. RPF could be fragmented effectively, with over 95 % disappearing after one pass of kneading and 10 min of beating. Consequently, it may be possible to use PA-coated paper cups as a raw material in the paper recycling process.