Development and Optimization of Chemical Deinking of Laser-Printed Paper

Abstract:

For the recycling paper process, the main problem is a high residual ink left on the paper, affecting the recycled paper's quality. Especially for laser-printed paper, ink strongly interacts with the paper fiber. A conventional chemical deinking has been used to remove laser ink with a high deinking efficiency but a low yield of recycled paper pulp. Recently, enzymatic deinking has gained attention due to its friendly environment. However, a complex procedure is required, and ink removal efficiency is lower than the conventional method. This research aims to simplify a chemical deinking process by decreasing reaction time, optimizing chemical components, and reducing experimental steps. Without pulping step, the laser-printed paper sheet was immersed in the chemical solution for a specific time, and the ink was removed by water spray. Results revealed that the chemical solution containing 1.5% sodium hydroxide, 2% sodium silicate, 1% hydrogen peroxide, and 0.3% tween-80 with a reaction time of 5 min at 60°C gave the highest paper yield of 97.3% and the lowest dirt count of 89.0 mm²/m². The final product was still in the form of a paper sheet.

• Periodical: Materials Science Forum (Volume 1098)
• Pages: 151-155
• DOI: https://doi.org/10.4028/p-ScgSt8
• Online since: September 2023
• Authors: Raktawan Muangnamsuk, Santi Chuetor, Suchata Kirdponpattara*
• Keywords: Chemical Deinking, Dirt Count, Laser-Printed Paper, Paper Sheet, Recycling

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