<p>Since recycling of waste paper is an important problem for environmental protection, the paper industry strives to improve the utilization rate of used paper. On the other hand, maintaining the quality of deinked pulp is becoming important as the demand level of quality for deinking pulp has become higher.</p><p>In recent years, printed matters by UV curable ink have been increasing for environmental reasons such as energy saving and no content of VOC （volatile organic compound）. The UV curable ink is a factor that signifi cantly reduces the quality of the deinked pulp because the conventional deinking method is not applica ble to miniaturize UV cured ink which forms strong fi lm.</p><p>So far, conventional drying oils based ink （oxidation and polymerization drying ink） using for newspaper etc. is relatively easy to miniaturize. However the ink is too adhesive to remove, then lead the problem of the diffi culty to improve the quality of deinking pulp even if further operation condition is optimized such as the fl otation process and the dosage of bleaching agent like hydrogen peroxide.</p><p>To provide the solution of these problems, weʼve successfully developed “catalyzer–type de–inking agent” combining the techniques of interface science and catalyst science for the fi rst time in this industry.</p><p>On the other hand, matters called pitch（dust, dirt）–are generated during the production process of pa per using waste paper. There are a lot of origins of pitch such as the adhesive for postal slip, back glue and resins in coating agents. As conventional pitch control agent provide only the performance of solubilization, emulsifi cation and dispersing of resins, in some cases, pitch is generated due to aggregation and giant growth of particles by demulsification or dispersion–break which are caused by external factors like pH change, shear force and addition of fi xing agent like aluminum sulfate.</p><p>These pitches adhere to paper, or paper manufacturing equipment such as aging towers, concentrators, rolls, dryers, etc., in some cases, the accumulated pitches drops off and re–adheres to paper. This reattachment causes problems such as quality loss of paper and decrease in productivity and workability due to paper breakage.</p><p>In particular, waste paper recycling plants are facing this pitch （dust, dirt） problem as the same level of frequency as the problem by UV cured ink. Thus the development of the new generation of pitch control agent as the solution of pitch problem has been requested for many years in the paper industry.</p><p>In this paper, we further introduce newly developed “hydrolyze–type pitch control agent” by applying the catalyst technology of “catalyzer–type deinking agent”. This new pitch control agent accelerates dissolution of pitches and prevents giant growth by decomposing the resin.</p>