Appeal No. 1999-0791
Application No. 08/754,884
The subject matter on appeal relates to a process for
delignification and bleaching of a chemically digested
lignocellulose-containing pulp. Further details of this
appealed subject matter are recited in illustrative claim 30
reproduced below:
30. A process for delignification and bleaching
of a chemically digested lignocellulose-containing
pulp, wherein the pulp is bleached at a pH in the
range from about 1 up to about 6 with a bleaching
chemical selected from the group consisting of
chlorine dioxide, ozone, peracetic acid and acid
peroxides, whereupon a water-soluble chemical
containing magnesium is added at a pH in the range
from about 1 up to about 7 and in an amount of from
about 0.01 up to about 10 kg/ton of dry pulp,
calculated as magnesium, and that subsequently the
pulp is bleached with hydrogen peroxide at a pH of
from about 8 up to about 12.
The examiner relies on the following prior art references
as evidence of unpatentability:
Loquenz et al. 4,834,837 May 30, 1989
(Loquenz)
Mauno Ruhanen and H.S. Dugal (Ruhanen), "First-Stage
Bleaching of Softwood Kraft Pulp with Peroxide, Instead of
Chlorine," TAPPI Journal 107-110 (Sep. 1982).
N. Liebergott, B. van Lierop, B.C. Garner, and G.J. Kubes
(Liebergott), "Bleaching a Softwood Kraft Pulp without Chlorine
Compounds," TAPPI Journal 76-80 (Aug. 1984).
Claims 30 through 36 and 38 on appeal stand rejected under
35 U.S.C. § 103 as unpatentable over Liebergott in view of
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