Appeal No. 1997-4290
Application No. 08/218,647
90% wood pulp weight in relation to the weight of the initial wood.” (p. 2, ll.
4 to 6). Lachenal discloses the wood pulp can be subject to a chemical treatment
which employs hydrogen peroxide in two stages wherein 10% or less of the
peroxide is used during the first stage. (p. 5 and the examples). Lachenal discloses
bleaching mechanical wood pulp consists of using chemical means to discolor
chromophor groups. (p. 2, ll. 7 to 11). Hydrogen peroxide is disclosed to be
suitable for bleaching processes which are either an alkaline environment or acid
environment. (p. 5) Lachenal discloses it was known that peroxide can be recycled
and can account for up to 20 % of the peroxide used in the bleaching process. (p. 3,
ll. 9 to 26).
The Examiner asserts that it would have been obvious to use a smaller
amount of hydrogen peroxide in the first stage and a larger amount of hydrogen
peroxide in the second peroxide stage because Lachenal teaches using 10% or less
of the total amount of peroxide in the first of two peroxide stages improves
bleaching while reducing the composition of hydrogen peroxide. (Answer, p. 3.)
We do not agree. The Examiner has attempted to combine the teachings of
Andersson ‘590, which is directed to chemical pulp, with the teachings of Lachenal,
which is directed to mechanical pulp. In the bleaching of chemical pulp, the lignin,
pitch, carbohydrate degradation products, chromophores and uv-absorbing materials
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