Nissin Kagaku Kenkyusho Co. Ltd.

In recent years, the paper industry has been faced with the problems of increased pitch sticky problems due to an increase in the amount of pitch in recovered paper caused by a decline in the quality of it and an increase pitch in pulp.One of the methods used to prevent pitch problems is the use of pitch sticky control agents.We are working to solve pitch problems throughout the entire process by using the appropriate agent for each process, and we call NISSIN Pitch Control Method(NISSIN-PCM).Conventional pitch evaluation methods could measure the total amount of pitch or evaluate coarse pitch, but could not evaluate fine colloidal pitch.Because white water and pulp slurry contain many components other than pitch, flow cytometry has low measurement accuracy.We visualized the pitch by image anal. using a fluorescence microscope, which enabled us to evaluate fine colloidal pitch.Using this method, when a pitch sticky control agent was added to the pulp slurry, a decrease in coarse pitch and an increase in fine pitch were observed in the filtrate.Thus, it was confirmed that the pitch control agent detached the fine colloidal pitch from the pulp and dispersed it in the liquidCombining these results with conventional pitch evaluation methods may lead to the development of new evaluation methods and pitch sticky control agents.

The paper industry is promoting the recycling rate and environmental load reduction to increase the utilization rate of used paper and to closed system, and it is exposed to an environment where pitch troubles due to sticky substances are likely to occur.In recent years, pitch troubles in the papermaking process have tended to increase and become more complicated due to a decrease in the amount of high-quality waste pa- per distributed due to restrictions on the import of mixed waste paper in China and an increase in the utilization rate of planted trees such as Akashiya.This is one of the troublesome issues for paper manufacturing engineers aiming for stable operation and quality improvement.Since its founding in 1931, we have proposed NISSIN-PCM (Nissin Pitch Control Method) as the most important way of thinking about pitch measures, and have been searching for new proposals for solving pitch problems to this day.Among these efforts. we consider that it is the most important to take optimal pitch measures in the quality process, and believe that implementing local and necessary pitch measures in each process will lead to improved quality and productivity of paper products.In this paper. we describe our latest approach to pitch problem solving.