DETACHMENT OF PRINTING INK FROM DIFFERENT TYPES OF FIBERS

Papers produced from different types of fibres were Printed with a new s offset ink. The printed papers were aged and then deinked in a speci ally designed washing cell, which facilitates a complete removal of th e detached ink from the fibres. The results showed that aging of the p rint severely affected the deinkability of the papers. It was shown th at ink was more difficult to detach from the fibres after the print ha d been aged, thereby affecting the final brightness of the pulp. No di fferences in detachment ability were found between different types of fibres. Aging of the print also affected the formation of small ink pa rticles. Tbe amounts of Very small particles in the submicron range we re considerably higher in the case of the aged samples. Beating the pu lp before sheet forming and printing affected the deinkability by yiel ding a pulp of higher brightness, which may be explained by the genera tion of fine material by beating, which facilitates the detachment and removal of the printing ink.