In Akzo Nobel Coatings, Inc. v. Dow Chemical Co., Appeal Nos. 2013-1331, -1389, Akzo sued Dow Chemical for infringing a patent related to extruding material at high pressure. After a combined claim construction and early summary judgment hearing, the district court granted Dow’s motion for summary judgment of non-infringement both literally and under the doctrine of equivalents. Akzo appealed the district court’s claim construction and summary judgment rulings. Dow Chemical cross-appealed the district court’s conclusion that the asserted claims are not invalid for indefiniteness.

The claims at issue require a “pressurized collection vessel.” Akzo argued that the district court’s construction of this term improperly required material to accumulate in the vessel. The Federal Circuit disagreed, noting that accumulation is required to give meaning to the claim term “collection” and to remain consistent with the examples provided in the specification. 

Regarding infringement, Akzo’s expert declaration and other proffered evidence did not explain how material accumulated in the vessel of the accused products, as the court’s construction required. Thus, the Federal Circuit found Akzo had failed to raise a genuine issue of material fact as to whether the accused product contained a “pressurized collection vessel” or performed the same function as the asserted claims in substantially the same way. Accordingly, the Federal Circuit affirmed the district court’s summary judgment rulings of no direct infringement and no infringement under the doctrine of equivalents.

Regarding Dow’s cross-appeal, the Federal Circuit further affirmed the district court’s holding that the claims were not indefinite, finding that the district court did not clearly err in relying on an expert declaration that one of skill in the art would interpret a limitation requiring “viscosity below 10 Pa.s” to be measured at room temperature in the absence of a specified temperature.