Appeal No. 2002-1791
Application No. 08/588,945
See our earlier decision on Appeal No. 1999-1007 (Application
08/708,998) entered March 31, 2000. The dispositive question is,
therefore, whether it would have been obvious to employ the
above-mentioned aromatic carbodiimides as crosslinking agents for
a waterborne coating binder polymer bearing at least two
carboxylic acid groups. On this record, we answer this question
in the affirmative.
As found by the examiner, both Taylor and Mellon teach
employing polycarbodiimides in general, including those made from
aromatic/aliphatic isocyanates, as a crosslinking agent for a
carboxylated latex resin or neutralized carboxylated water
soluble polymer. See Taylor, page 2, lines 24-33, and Mellon,
page 2, lines 28-38. “The resin systems in which carbodiimide
cross-linkers are particularly useful are those in which the
material contains reactive carboxyl groups, such as are typically
found in aqueous latexes used for coatings.” See, e.g., Taylor,
page 2, lines 34-36. The polycarbodiimides, especially the
aromatic polycarbodiimides3 described in Hoeschele, modified
Mellon, motivated by a reasonable expectation of successfully
further enhancing the dispersibility (dissolving) characteristics
of the aromatic polycarbodiimides.
3 We note that Hoeschele teaches that its preferred aromatic
polycarbodiimides have advantageous properties, e.g., compressive
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