Appeal No. 2004-1877
Application No. 09/178,512
heating the hardwood chip material to a temperature
above 120°C;
(c) treating the hardwood chip material with a third
alkaline liquid having a third effective alkali
concentration at a temperature greater than 140°C to
delignify the material; and
(d) treating the hardwood chip material with a fourth
liquid to cool the material to a temperature less
than 120°C; wherein the first, second, third initial
effective alkali concentrations are all less than
30 g/L, and wherein the second and third effective
alkali concentrations are about 25 g/L or less.
The examiner relies upon the following references as
evidence of obviousness:
Kettunen et al. (Kettunen) 5,635,026 Jun. 3, 1997
Chasse et al. (Chasse) 5,674,359 Oct. 7, 1997
P. Sandström et al. (Sandström), "Development of Modified Kraft
Processes With a Mathematical Model for Continuous Digesters,"
1 ACME Forest Products Division 31-42 (1986)
Appellants' claimed invention is directed to a method for
producing cellulose pulp from comminuted fibrous hardwood chip
material. The method entails treating the hardwood chip material
with first, second and third alkaline liquids at increasing
temperatures, i.e., first at less than 120°C, then at a
temperature above 120°C, and finally at a temperature greater
than 140°C. The treated chip material is then exposed to a
fourth liquid which cools the material to a temperature less than
-2-
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