- 期刊
影印廢紙之脫墨再生
De-inking of Xerographic Wastepaper for Recycling
摘要
影印廢紙是由高品質的化學紙漿製成的，若能善加回收再生，可減少由木材製造紙漿的能源、藥品、污染及CO_2的排放，更能減少森林的砍伐，對於環境的保護，實具有重大的意義。然而，影印廢紙之再生最大的難題是附著其上的油墨不易分離，因而導致再生紙上之黑墨斑點嚴重的影響印刷品質而不適於閱讀。影印廢紙上的油墨主要是由黑色的碳粉散佈於熱塑性的塑膠而組成，此塑膠具有疏水性，不溶於傳統的脫墨劑中。本研究依據塑膠的溶解度參數、玻璃轉移溫度（Tg）及表面張力等物理性質，以合適的溶劑及界面活性劑設計調配得新的脫墨劑，結果可分別以2種方法得到高效率的脫墨。其一是乳化法：可利用脫墨劑使油墨生成微細的乳液（527nm），藉由壓榨、洗滌而分離。此含墨之廢乳液可藉由脫墨劑中非離子界面活性劑的混濁點性質加熱而分層，便於回收疏水性的藥劑及油墨，以避免2次的廢水污染，但使用的脫墨劑（7 wt%）及用水量較多為其缺點。其二是塑片粘墨法：可利用脫墨劑使油墨生成粘滯物而粘附在額外加入的塑膠材料中，再藉篩選而分離。此方法的脫墨劑添加量較少（0.8 wt%）且廢水是透明的，廢水和吸墨的塑膠材料都可以回收而重複使用。此兩種方法均可在20℃，1atm，10分鐘內使再生紙上之殘墨量由67900 mm^2/m^2降低至10 mm^2/m^2以下，墨粒的移除率達99.98%，再生紙的白度則可由80%GE提高至85%GE，幾乎達到未印刷原紙的86%GE，已適合再用於印刷之用紙。相對於傳統脫墨法（洗滌法及浮選法）需於80℃，1atm，90分鐘的處理，較省能量，脫墨效率亦較佳且可用傳統的設備，頗具經濟價值。
並列摘要
The photocopy papers such as xerographic and laser printed are generally made from high guality chemical pulps and are substantial: minimizing investment capital, saving raw materials and energy cost, cutting down odor, and reducing wastewater and carbon dioxide emissions. However, a successful recycling of photocopy wastepaper is often hampered by the de-inking problems. It is well known that the xerographic or laser toner has been one of the most difficult inks to be removed efficiently. The residual black ink specks of recycled papers make them unsuitable for copying. In toner's binder resins, carbon blacks or other pigments are generally dispersed in thermoplastic polymers. The polymer components are highly hydrophobic; they do not dissolve readily in water or in inorganic de-inking agents. This research aimed at designing and developing new de-inking agents with reference to the physical properties of toner polymeric binders such as solubility parameter, glass transition temperature and surface tension. We developed a new de-inking additive that consists of 0.8 wt% NAISA20 as de-inking solvent and 0.3 wt% LAUEO3 as the surfactant. The additive is used in a PET film-assist adsorption de-inking process. The optimal condition for the new de-inking process was carried out at 20°C for 7 minutes. The residual ink speck population in the regenerated paper is reduced from 67900 ppm to about 12 ppm (99.98% improvement). The brightness of the final deinked pulps is improved to 85% GE, almost identical to 86% GE of the virgin paper. The main advantages of the new de-inking process are that it requires low dosages of chemicals and low energy consumption. The wastewater and the plastic films used in the process can be easily recycled. This simple and practical process can be easily and economically adapted to conventional de-inking plants.