Some aspects of the problem of «harmful resin»

A lot of authors investigated the chemical composition and properties of «harmful resin» which is a reason of significant economic losses in the pulp and paper production. However up to the present time there is no clear idea about this. A number of researchers connected «disutility» with colloidal-chemical condition. It was earnestly proved in the manuscript, that resin emulsified in the sulphite liquor at the end of cooking coagulates because of cooling and instability with precipitation on the cellulose fibers that could be a reason of further pitch troubles in the production. It was considered that «harmful resin» appears only from derivatives of wood extractives: resin, fat acids, fats, and unsaponifiables. However the investigation of the sedimentation instability of each group of black liquor organic substances (extractives, kraft lignin, wood carbohydrate derivatives) and mixture of all components in the real black liquor and the sorption of them by cellulose showed, that the coagulated «harmful resin» on the fiber surface after cooking contains except extractives also kraft lignin, carbohydrate derivatives of wood, where the last are in significant amount.