Appeal No. 1996-2350
Application 07/843,833
a mixer, the digested, unbleached pulp at a low alkaline pH
with a mixture of ozone and oxygen pressurized to between
about 60 psig and about 100 psig in an initial, chlorine free
bleaching stage, said ozone in said mixture being present in
an amount of between about 0.15% and 0.5%, based on the dry
weight of the pulp, and wherein the temperature of said pulp
in said mixer is maintained below the temperature at which
oxygen will react with the components of
said pulp and at or above the temperature at which said ozone
will react with components of said pulp so that essentially
all of said ozone in said mixture is consumed by reaction with
the components of said pulp while a substantial portion of
said oxygen in said mixture remains unreacted in said pulp,
and thereafter altering the pH of said pulp to an alkaline pH
and increasing the temperature of said pulp containing said
oxygen to a temperature at which the oxygen in said pulp will
react with components of said pulp for a period of time
sufficient for said oxygen to react with said pulp components,
thereafter subjecting said pulp to a conventional water
washing step, and after said washing step, subjecting the
washed pulp to a further second phase including repeating the
aforesaid procedure employing the washed pulp and further
ozone/oxygen mixture.
The prior art references of record relied upon by
the examiner in rejecting the appealed claims are:
Phillips et al. (Phillips) 4,372,812 Feb. 08, 1983
Tsai (Tsai '124) 4,959,124 Sep. 25, 1990
Schwarzl 5,133,946 Jul. 28, 1992
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