EFFECTS OF REFINING ON FIBER CHARACTERISTICS AND PAPER PROPERTIES FOR ASPEN BCMMP

The fiber characteristics and paper properties were investigated during low consistency refining of aspen BCTMP. The results showed that by the method of fiber quality analysis and fiber classification, the increase of refining degree could reduce the long fiber fraction and increase fines fraction. At the same time, the average fiber length and fiber coarseness decreased gradually. The curl and kink index decreased, which was helpful to fiber stretching and improved the paper properties. During the refining process, the freeness decreased as well as paper bulk while the tensile and burst strength were improved gradually. At the freeness of 360mL, the weighted length and fiber coarseness decreased respectively by 2.1% and 5.1%, and fiber curl and kink index decreased by 8.0% and 5.0% respectively. Compared to the pre-refining pulp, paper bulk decreased by 10% while the stiffness, tensile index and burst index increased by 20%, 65.3% and 23.2% respectively, which indicated that paper physical properties were changed by refining with different amplitude influences. The balance between paper bulk and strength could be obtained by adjusting the fines content in refining.