Appeal No. 2004-1877
Application No. 09/178,512
be avoided by first ensuring that the wood, or other cellulose, is
penetrated with a relatively cold alkali at the beginning of the
impregnation" (column 1, lines 24-26). Chasse discloses that the
first alkali treatment zone is at a temperature of 80°-110°C,
which is within the claimed range of less than 120°C, and at an
alkali concentration of about 5-30 g/L, which meets the claimed
range of less than 30 g/L. The second treatment zone of Chasse is
conducted at a temperature between about 110°-150°C and at an
alkali concentration that is typically at least 5 g/L greater than
the first treatment zone. It can be seen that the temperature and
alkali concentration in Chasse's second treatment zone largely
overlap the recited ranges for appellants' second treatment zone.
Finally, Chasse cooks the cellulosic fibrous material at a
temperature in the range of 150°-180°C, which meets the claim
recitation of greater than 140°C (see column 1, lines 60-62).
Although Chasse does not expressly disclose the level of alkali
concentration in the cooking step, it is reasonable to conclude
that the concentrations of less than 30 g/L present in the first
two treatment zones would also prevail in the cooking zone.
Significantly, appellants' specification discloses that it was
conventional in the art for the alkali concentration to decline
during the course of treatment such that the final concentration
-4-
Page: Previous 1 2 3 4 5 6 7 8 9 Next
Last modified: November 3, 2007