Appeal No. 96-2810
Application 08/017,086
disclosure.
The court reemphasized at 473, 5 USPQ2d at 1531:
There must be a reason or suggestion in the art for
selecting the procedure used, other than the knowledge
learned from the applicant’s disclosure.
It is precisely that requisite reason or suggestion to employ
a hydrophobically modified cellulose ether in a ceramic glaze
for use in a process for glazing sanitary ceramic articles
which the combined prior art teachings lack.
Norris adds a small amount of a naturally occurring or
synthetic water-soluble polymer gum as a thickener to form
stable dispersions of up to 70% colored ceramic pigments for
ceramic glazes (Norris, Abstract and col. 7, l. 18-20).
Xanthan gum appears to be the preferred thickener (Norris,
Abstract and
col. 7, l. 22-24). Norris teaches (Norris, col. 7, l. 28-38):
Modified cellulose ether gums such as hydroxy cellulose,
methyl cellulose, hydroxy propylmethyl cellulose and
sodium carboxymethyl cellulose may be used. . . .
Because of a greater tendency of . . . synthetic polymers
to cause undesirable gelling of the dispersion, they are
less preferred than the gums. The optimum levels of
these
thickeners in the slurries can be readily determined by
routine experimentation.
On the other hand, Lo recognizes that water soluble
cellulose ethers, particularly hydroxyethyl cellulose (HEC),
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