MODIFIED KRAFT HARDWOOD PULP YIELDS HIGH-BRIGHTNESS AND HIGH-STRENGTH

The acute demand for high brightness is generating interest in the dev elopment of new pulping and bleaching technologies. The conventional h ardwood kraft pulp (kappa 20) was found to be unsatisfactory largely d ue to its inability to meet the twin objectives of 90% ISO brightness and acceptable strength. These objectives can be achieved through modi fications in the existing pulping and bleaching process. The use of ka ppa number 30 hardwood kraft pulp and extending the delignification by oxygen to a kappa number of 11 was found to be an effective way of ac hieving high brightness (90% ISO) with maximum cleanliness, at the sam e time maintaining the high strength properties. The performance of th e modified pulping process was evaluated with various bleaching sequen ces for achieving high brightness and strength.