Appeal No. 2003-0606
Application No. 09/281,837
(95.5°C) to raise the temperature of the hot blown film to above
its orientation temperature" (page 4 of Brief, third paragraph).
We are satisfied, however, that the examiner has refuted this
argument at page 5 of the Answer. The examiner's rationale at
page 5, second full paragraph, follows:
Savage teaches how to make water soluble cellulose
ethers. The process uses a highly concentrated aqueous
alkali cellulose solution of 30-60% (2:19-26) in a two
stage reaction. The reaction temperatures include a
first stage at 30°-40°C, and a second stage of 40°-80°C
(2:19-36). The end product, which is a highly
concentrated solution, forms a gel when cooled to below
45°-50°C (2:44-45). Appellant's [sic, appellants']
argument has incorrectly assumed that a gel is formed
"above" 45°-50°C. Rather, this gel point is actually a
cloud point or the temperature at which the soluble
cellulose ether precipitates from the solution in the
form of a gel (rather than a powder). Thus, Savage
suggests that a cellulose ether solution requires
heating above 40°C-50°C (104°-122°F) to remain in
solution. For example, Salzinger uses a very dilute
solution, 0.2% w/w, when coating a film (4:50-60) and
dries the solution at 80°C. The slow evaporation of
water at this temperature likely allows a good coating
to form uniformly across the polymeric film. However,
if appellant's [sic, appellants'] argument is correct,
then the solution would gel upon heating before
reaching the drying temperature and therefore would be
unable to form a desirable coating. It is also noted
that Savage teaches that the thermal stability, or
decomposition temperatures, of the water soluble
cellulose ethers is above 250°C as shown in Table 1
(3:16-32) which further suggests that the cellulose
ether would not be effected by the process temperatures
used in the process of Schirmer.
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