Appeal No. 1996-0647
Application No. 07/871,401
chlorine-containing moieties and render the same soluble in
the acid medium of said pulp,
thereafter, separating said solubilized chlorine-
containing moieties from said pulp, and
whereby there is obtained a pulp having substantially
lower chlorine content, essentially no 2, 3, 7, 8
tetrachlorodiben zodioxin, essentially no 2, 3, 7, 8 tetra-
chlorodibenzofuran, and substantially equivalent brightness
and viscosity as the same pulp which has been bleached
employing conventional chlorine-based bleaching sequences.
7. A bleaching sequence for kraft pulp consisting of the
stages of D ZED in that order with no other stages either
c
before, in-between or following the stages of this sequence
other than washing stages.
8. A cellulosic kraft pulp suitable for papermaking
purposes, said pulp being bleached through the use of chlorine
dioxide or a mixture of chlorine dioxide and chlorine, being
essentially free of 2,3,7,8 tetrachlorodibenzodioxin or
2,3,7,8 tetra[sic, chloro]dibenzofuran, having a total organic
chloride content of less than about 200 ppm, based on pulp,
and having a total adsorbed organic halogen content of less
than about 2kg/ton, based on pulp.
The examiner has relied upon the following references as
evidence of obviousness:
Nonni 4,568,420 Feb. 4, 1986
Granum et al. (Granum), “Influence of Bleaching Chemicals and
Sequences on some Properties of Suphite Pulps”, Journal of
Pulp and Paper Science, pp. J25-J29, March 1984.
Kringstad et al. (Kringstad), “Bleaching and the Environment”,
TAPPI Proceedings, 1988 International Pulp Bleaching
Conference, pp. 63-68, Orlando, Florida, June 5-9, 1988.
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