The effect of printed coated papers on the deinking of mixed office waste with 1-octadecanol

Mixed Office Waste paper (MOW) is a source of recyclable fiber that is not fully used because of difficulties in removing some types of ink. Our previous work [5-7] has solved the problem of removing toner ink from photocopied paper, which is the major difficulty in MOW deinking. Among the chemicals used, 1-octadecanol is the most effective for improving toner ink detachment from fibers and the subsequent agglomeration. When used directly for MOW deinking, it is not as effective as for 100% photocopied paper. This research work investigates why coated papers and oil-based ink printed on the coated paper interferes with the toner ink removal using 1-octadecanol. The coating materials in both "EURO ART" and "SPectraTech" coated papers do not interfere with toner ink detachment, but they adversely affect subsequent toner agglomeration when the coated paper ratio in a pulp slurry exceeds 50%. Oil-based ink itself does not affect toner ink detachment or agglomeration. However, the oil-based ink printed on 'SpectraTech' coated paper and uncoated copy paper cannot be completely detached during the pulping step, including the 1-octadecanol treatment, resulting in incomplete deinking. Experimental results convinced us that the difficulty occurs during the pulping step. An improved pulping step carried out at 75 degrees C and pH ii can completely detach the oil-based ink on both coated paper and copy paper resulting in complete deinking when carried through a subsequent flotation stage.