Appeal 2007-2910
Application 10/304,881
1 secondary considerations guard against the employment of impermissible
2 hindsight.20
3 The scope and content of the prior art
4 The Robeson patent teaches a curable polymer emulsion composition
5 containing a blend of an epoxy polymer and a vinyl acetate polymer. An
6 amine curative can be used for long-term stability.21 Robeson explains that
7 epoxy resins must be cured with a suitable hardener, generally an amine, but
8 that combining them in a water-based solution reduces storage stability.22
9 Robeson reports that the problem can be overcome by using
10 isophoronediamine (IPDA) as the amine curative for the epoxy resin.23
11 Robeson's improved composition is said to be suitable for coatings and
12 adhesives.24
13 Robeson teaches that a broad range of epoxy resins could be used, but
14 the preferred epoxy resin is the diglycidyl ether of bisphenol A. The "di-"
15 prefix in diglycidyl ether simply means that there are two glycidyl ether
16 groups, one formed at each hydroxyl of the bisphenol A moiety.25 Robeson
20 Graham v. John Deere Co., 383 U.S. 1, 17, 36 (1966), cited with approval
in KSR Int'l v. Teleflex Inc., 127 S. Ct. 1727, 82 USPQ2d 1385 (2007). The
record on appeal does not contain objective evidence of secondary
considerations.
21 Robeson 1:14-23.
22 Robeson 1:37-44.
23 Robeson 2:52-58. Air Products' dependent claims 14 and 15 permit and
require, respectively, that the amine be IPDA.
24 Robeson 3:9:13.
25 Robeson 4:18-20. Where the bisphenol A is a repeating unit in a polymer
chain, the glycidyl ethers are formed at the terminal hydroxyls.
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