Comparison of the Effect of TMP Pitch Control Agents with Different Mechanisms

. The pitch contained in thermomechanical pulp (TMP) negatively affects paper quality, pulp, and the papermaking process. Serious pitch and stickies problems may occur in paper recycling processes. In this study, the effects of chemicals used to control the pitch in the TMP process were compared. The method used to analyze the pitch control effect was to perform image analysis after using a reagent that selectively stains only the hydrophobic pitch. Three different mechanisms, namely fi xation, detacki fi cation, and dispersion, were applied to solve the pitch problem from TMP. All the control agents were effective in pitch control, and, in particular, the agents related to fi xation and dispersion were found to be more effective in reducing the number and area of tacky particles per unit area in sheets and white water. However, it was dif fi cult to clearly identify the effect of both the detacki fi ers and the dispersant agents through image analysis after staining except for the fi xative agent.