| 摘要 |
<p>PROBLEM TO BE SOLVED: To make foam regulation consistent with ink-removing effects by applying a mixture of ink-removing agents comprising a specific compound and a specific nonionic surfactant. SOLUTION: This method for removing ink is to mix a compound expressed by the formula (X1 and X2 are each H, NH2, NH-NH2 or the like; X3 is O, S, NH or SO2), preferably urea with an ink-removing agent comprising a nonionic surfactant having a 14-44C hydrophobic residue, e.g. an ink-removing agent comprising an ethylene oxide/propylene oxide-added stearyl alcohol in weight ratios of 1/99-99/1, preferably 30/70-70/30 and add 0.001-5 pts.wt. of the mixture to 100 pts.wt. of raw used paper in a floatation process to remove ink.</p> |
