Patent ID: 6458245
Filing Date: 2002-10-01
Classification: B27N,D21B,D21C

Abstract:
An absorbent chemithermomechanical pulp produced from lignocellulosic material consisting of wood chips at a wood yield above 88%, by a process comprisinga) steaming the wood chips; b) impregnating the chips with a warm impregnating solution having a temperature of at least 130Â° C., and selected from the group consisting of sodium sulphite, sodium dithionate and alkaline peroxide, with an addition of a complex building; c) preheating the chips at a temperature of 150-175Â° C.; d) carrying out steps b) and c) in one and the same vessel over a combined time period of at most 2 minutes by impregnating the chips with said impregnating solution; e) defibering the chips to pulp at substantially the same pressure and temperature as those employed in the preheating process; and f) washing and dewatering the pulp, said pulp having a resin content below 0.15%, calculated as the amount of resin that can be extracted in dichloromethane, a high long-fibre content, a low-short-fibre content and a low shives content, said pulp further having such a brightness that it can be bleached with peroxide to a brightness of at least 65% ISO, wherein when fractioning according to Bauer McNett, the long-fibre content is above 75% of fibers retained on a wire gauze of size 28 mesh and the short fibre content is below 8% of fibers which pass through a wire gauze of size 200 mesh; and wherein the shive content is lower than 3% measured according to Somerville, and said pulp being a fluff pulp having been refined to a freeness of 760 ml CSF at the lowest.