Patent ID: 6267841
Filing Date: 2001-07-31
Classification: D21B,D21C

Abstract:
A method for pulping wood chips comprising the steps of:(a) feeding the wood chips to a primary refiner zone operating at a temperature of above about 145.degree. C. and at an energy level of less than about 10 hpd per ton for a time to cause substantive separation of wood fiber comprising said wood chips without causing substantial reduction in the average length of said wood fibers to form pulp comprising said wood fiber having a lignin coating on an outer surface of said fiber;(b) treating the pulp form step (a) with an enzyme in the substantial absence of treatment chemicals in an amount and for a time sufficient to weaken the strength of the lignin coating to form treated pulp; and(c) further refining the treated pulp in a second refiner zone operating at an energy of less than about 20 hpd per ton to form a processed pulp comprising wood fiber having a reduced amount of lignin coating wherein the average length of said wood fiber is at least about 80% of the average length of wood fiber in said wood chips.