Appeal No. 1998-2077
Application 08/553,324
7-8. In contrast to the sequence required by the claimed subject matter, the process of Backlund
comprises first treating delignified pulp with a chelating agent such as EDTA. See column 1, lines 26-
28. Thereafter, the pulp is bleached with hydrogen peroxide, followed by a treatment with ozone. See
column 1, lines 33-36, column 2, lines 7-10, and 23-26. An additional peroxide stage may follow the
ozone treatment. See column 2, lines 38-40. This sequence in the process is designated as QPZ or
QPZP. See column 2, lines 45, 49, and 55-56. Backlund teaches that washing occurs after each
treatment stage. See column 3, lines 42-59 and claim 1. We conclude that this sequence is distinct and
different from that of the claimed subject matter.
Similarly, we find that Lundgren describes a process for treating delignified pulp with a chelating
agent followed by a peroxide treatment. See Abstract, and column 1, lines 7-11, and column 3, lines
30-44. The complexing agent among others includes EDTA. See column 3, lines 58-63. Washing is
disclosed between the stages Q and P. See Example 4. The process may be designated as QP.
There is, however, neither a disclosure nor a suggestion for the utilization of ozone or an ozone
treatment at any stage in Lundgren.
As to Lindberg, we find that Lindberg discloses a method for bleaching pulp without using
chlorine chemicals. See column 1, lines 9-12. The method comprises removing transition metals from
the pulp by (a) treating the pulp with an ozone stage or a chelation stage. See column 2, lines 11-20
and 29-34. The treated pulp is thereafter washed. Id. See also claim 1. The sequence outlined in the
detailed description of the drawings is a chelating stage, followed by washing, followed by bleaching, or
4
Page: Previous 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 Next
Last modified: November 3, 2007