Appeal No. 1999-0791
Application No. 08/754,884
Ruhanen. (Examiner’s answer, page 3.) Also, claim 37 on appeal
stands rejected under 35 U.S.C. § 103 as unpatentable over
Liebergott in view of Ruhanen and Loquenz. (Id.)
We reverse these rejections.
According to the examiner (id.), Liebergott describes
"chemical pulps in a Z-P [ozone-hydrogen peroxide] bleach
sequence...wherein the pH is 2.3 in the ozone stage and a pH of
10.6 in the [hydrogen] peroxide stage." The examiner, however,
recognizes that Liebergott does not teach the addition of a
"water-soluble chemical containing magnesium" in the manner as
recited in appealed claim 30, the sole independent claim on
appeal.
To account for this difference, the examiner relies on the
teaching of Ruhanen. Specifically, the examiner held: "It would
have been obvious to treat the ozone-acid treated pulp of
LIEBERGOTT ET AL with a magnesium salt prior to the peroxide
bleach stage as such is taught by RUHANEN to improve the
brightness of the peroxide bleaching." (Id.) We cannot agree
with the examiner's analysis.
Ruhanen teaches:
Sulfite pulps could be bleached more easily with
peroxide than kraft pulp without acid pretreatment, as
can be seen from Table I. After acid pretreatment,
however, the peroxide bleachability of kraft pulps
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