Opinion ID: 460292
Heading Depth: 2
Heading Rank: 3

Heading: 1 General Level of Skill in the Art

Text: 79 The district court found that British Patent No. 1,031,909, although technically not prior art, was indicative of what was generally known during the relevant time frame to persons of ordinary skill in the foundry art. Finding that the British Patent described reacting novolac resins with highly reactive divalent materials 35 to produce soluble, fusible polymers which may be employed as binders for sand (foundry resins), the court concluded that the British Patent disclosed the use of phenolic urethanes as foundry binders. 36 The court also found that U.S. Patent Nos. 3,398,122 and 3,409,571 (the '122 and '571 patents, respectively), issued to Shepard, were significant for a teaching that phenolic urethanes were useful as constituents of foundry binders. Shepard, the court found, described a soluble thermoplastic, i.e., a novolac phenolic resin modified with a phosphorous compound, which could be mixed with polyisocyanates to form thermosetting products useful in foundry sand binders. Based upon the district court's findings with respect to the Shepard references, we cannot say that the district court erred in concluding that phenolic urethanes were taught as having utility in foundry binders. C.2 The Shepard Patents 80 The district court found that one skilled in the art could also readily sense that the 'Pep' resin might be substituted into the Shepard patent. Since it was known in the prior art how ether bridges and hydroxyl groups reacted with polyisocyanates, 37 one of ordinary skill in the art could have looked at the Rothrock patent, MEGSON, and MARTIN, analyzed their teachings in light of the Shepard patents and the British Patent, 38 and concluded that a polybenzylic ether resin could have been plugged into Shepard to produce a phenolic urethane foundry binder. 81 The district court's conclusion that the Pep resin might have been substituted for the phenolic condensate used in the Shepard patent is erroneous as a matter of law, for several alternative reasons. 39 First, the district court failed to consider the '571 patent in its entirety, in particular for those teachings therein that would have led one skilled in the art away from the subject matter of the '392 and '579 patents. W.L. Gore, 721 F.2d at 1550, 220 USPQ at 311. The specification of the '571 patent taught that the thermoplastic products of the invention could be used to produce thermosetting products by curing the thermoplastic products with agents, such as, inter alia, polyisocyanates. The specification disclosed further that these thermoplastic products and/or thermosetting products were useful as foundry sand binders. 82 But, the district court failed to consider what these thermoplastic products were disclosed to comprise. The '571 specification disclosed that these thermoplastic products were polymeric esters characterized in that: 83 NOTE: OPINION CONTAINS TABLE OR OTHER DATA THAT IS NOT VIEWABLE 84 Thus, the '571 specification taught that the thermoplastic product was more than a phenolic condensate. It was a phenolic condensate wherein a phosphorus-containing moiety had its unsatisfied bonds attached to the aryl nuclei of the same phenolic condensate. Even assuming arguendo that one skilled in the art might readily have sensed that the Pep resin of the '797 patent might have been used as the phenolic condensate called for by the Shepard patent, Shepard taught only that it was the polymeric ester or thermoplastic product, i.e., the phenolic condensate in combination with the bonded phosphorus-containing moiety, that could be reacted with polyisocyanates or tertiary amines to produce thermosetting products having utility in foundry sand binders. But, the teachings of Shepard did not disclose to one skilled in the art whether the phenolic condensate, by itself, would have had utility as a thermosetting product. 85 The district court found that one of ordinary skill in the art would have looked at the Rothrock patent, MEGSON, and MARTIN, analyzed their teachings in light of the Shepard and British patents, 40 and concluded that a polybenzylic ether resin could have been plugged into Shepard to produce a phenolic urethane binder. Based upon our holdings in Section A. CLAIM 10 OF THE '797 PATENT--PEP RESIN, supra, this conclusion is erroneous as a matter of law. In Section A we held that the Rothrock patent, MEGSON, and MARTIN, considered singly would not have led to the conclusion that the Pep resin as claimed in claim 10 of the '797 patent would have been obvious, and that there was no basis for combining the teachings of these references, such that one skilled in the art would not have had knowledge of the Pep resin as of the critical period. Therefore, there was no proper basis for the district court to conclude that one skilled in the art, even with knowledge of the teaching of the Shepard patent with respect to the utility of phenolic urethanes as foundry binders, would have had knowledge of a phenolic resin substantially similar to the phenolic resin as claimed in claim 10 of the '797 patent. Therefore, it was erroneous to conclude that the Pep resin of the '797 patent could have been substituted into the Shepard patent for use in producing a phenolic urethane foundry binder as taught in the Shepard patent. 86 C.3 Combining Prior Art with the Shepard Patents 87 Moreover, assuming for the sake of argument that the Rothrock patent, MEGSON, and MARTIN would have led one skilled in the art to a phenolic resin substantially similar to the phenolic resin as claimed in claim 10 of the '797 patent, the '571 patent contained relatively little in the way of positive suggestion or inference which would have led one skilled in the art to combine the teachings of these references with the Shepard patent. ACS Hospital Systems, 732 F.2d at 1577, 221 USPQ at 933. The '571 patent taught two methods for the preparation of phenolic condensates having a high percentage of ortho-ortho alkylidene linkages. 88 The preferred phenolic condensate was prepared by reacting an excess of phenol with formaldehyde, i.e., a phenol/formaldehyde ratio greater than 1, in the presence of an inorganic alkali catalyst. In contrast, the Rothrock patent taught a formaldehyde/phenol ratio of 1:1, or a range of 1:63 to 1:1. Further, the Rothrock patent taught that the resins thereof could not be produced in the presence of alkali catalysts. 89 The alternative process for producing the phenolic condensates described in the '571 patent involved reacting an aldehyde with a phenol in the presence of an acid catalyst. The ratio of formaldehyde/phenol was described as being in the range of 0.5 to 1.0, with the preferred range being 0.7 to 0.9. Thus, while the '571 patent taught a formaldehyde/phenol ratio range wherein the upper bound minimally overlapped the lower bound of the Rothrock patent formaldehyde/phenol ratio, the preferred range taught in the '571 patent diverged away from the ratio as taught in Rothrock. The '571 patent also taught that the acid catalyst could be hydrochloric, sulfuric or oxalic acids, and was silent as to the need for a solvent to effect condensation. The Rothrock patent, in contrast, taught that condensation occurred in the presence of both a mild acid catalyst, such as zinc acetate, boric acid, or copper acetate, and a completely volatile, non-gum-forming solvent, and further that resins could not be produced in the presence of strongly acidic catalysts, such as hydrochloric acid. Since the '571 patent appeared to have suggested stronger acid catalysts than those usable in the Rothrock patent, and was silent as to the use of a solvent, an uncertainty would have arisen as to whether the teachings of the Rothrock patent could have properly been combined with the teachings of the Shepard patent. 90 A further point is that the '571 patent taught that the phenolic condensate of the novel ester was one having at least 60 percent ortho-ortho alkylidene linkages. The specification disclosed that the term alkylidene expressed the structural relationship of the substituted methylene residues of the aldehyde to the phenolic nuclei of the phenolic condensates and that the term was intended to be generic to all such substituted methylene groups defined within the scope of the invention, and further taught that the phenolic condensates most useful in the invention were characterized by R2 -C-R2 linkages, wherein R2 could be independently selected from the group consisting of hydrogen, a hydrocarbon radical, and a halogen-substituted hydrocarbon radical. This teaching would have seemed to preclude the teachings of the Rothrock patent being combined with the teachings of the '571 patent inasmuch as the phenolic resin of the Rothrock patent which would have been substantially similar to the resin as claimed in claim 10 of the '797 patent would have had a majority of ether linkages, 41 not alkylidene linkages.