New peroxide activators for kraft pulp bleaching

摘要

This paper reports two new methods for enhancing the peroxide bleaching of kraft pulps. The methods involve the use of an alkylguanidine or alkylurea as a peroxide activator in the presence of an inorganic stabiliser for wood pulp bleaching. The activators were evaluated on various kraft pulps and their performances compared with commercially used peroxide activators. The results showed that both activators greatly improved the performance of peroxide bleaching processes under relatively mild conditions, and they were found to be superior to commercially used peroxide activators under the conditions examined. Alkylurea performed better than alkylguanidine over a broader temperature range. The use of the alkylurea did not negatively affect pulp viscosity. Potential limitations of the methods are also discussed.