In Akzo Nobel Coatings, Inc. v. Dow Chemical Co., the Federal Circuit upheld the district court’s grant of summary judgment of no infringement under the doctrine of equivalents because the patent holder had failed to establish a genuine issue of material fact under the function-way-result test. This case illustrates the scrutiny the court may apply to expert testimony cited to support infringement under the doctrine of equivalents. 

The Patent At Issue

The patent at issue was U.S. Patent 6,767,956, directed to an “[e]xtrusion process.” The Federal Circuit identified claim 1 as representative:

  1. A process for producing a dispersion of a polymer in an aqueous medium in which the polymer is dispersed in an aqueous medium in an extruder at a temperature above 100ºC in an extruder having an outlet

wherein the pressure in the extruder is maintained above atmospheric so that the aqueous medium does not boil characterized by maintaining the pressure above atmospheric for the extruder at the outlet with a pressurized collection vessel and

wherein aqueous dispersion from the extruder has at least 25% by weight of the aqueous medium where the aqueous medium has less than 40% by weight of organic solvent and

wherein the aqueous dispersion enters the outlet and pressurized collection vessel at a pressure above atmospheric so that the aqueous medium does not boil and is subjected to the action of a cooling zone to lower the temperature of the aqueous dispersion to below 100ºC to have an aqueous dispersion with a viscosity below 10 Pa.s.

Dow’s accused process, called BLUEWAVE™, is summarized in the Federal Circuit decision as follows:

[BLUEWAVE™] uses an extruder to generate low viscosity polymer dispersions. In Dow’s process, the dispersion exits the extruder, passes through a valve located at the extruder’s outlet, and then travels through a series of pipes and heat exchangers. The dispersion then continues on through a filter and collects in a “Product Tote,” an unpressurized compartment, eventually used to transport the end-product.

The District Court Decision

The district court construed “pressurized collection vessel” as as “tubing, piping, or other container where a desired material accumulates, which is maintained above atmospheric pressure.” The court found no literal infringement because Dow’s dispersion does not “accumulate” in its heat exchange equipment, and also found no infringement of this aspect of the claimed process under the doctrine of equivalents.

The Federal Circuit Decision

The Federal Circuit decision was authored by Judge Lourie and joined by Judges Reyna and Chen. The decision addresses several issues raised by Akzo’s appeal and Dow’s cross-appeal, but this article focuses on the doctrine of equivalents, because it seems like it has been a while since the court has discussed this area of law.

Akzo argued that the district court “committed legal error by applying the concept of vitiation and impermissibly creating ‘a “binary choice” in which an element is either present or “not present.”‘” The Federal Circuit disagreed, citing the Supreme Court decision in Warner-Jenkinson Co. v. Hilton Davis Chem. Co., 520 U.S. 17 (1997), for emphasizing the element-by-element nature of the doctrine of equivalents analysis:

A patentee must establish “equivalency on a limitation-by-limitation basis” by “particularized testimony and linking argument” as to the insubstantiality of the differences between the claimed invention and the accused device or process. …. The function-way-result test “often suffice[s] to show the substantiality of the differences.” …. “[A]ll claim limitations are not entitled to an equal scope of equivalents.” …. Ultimately, “many limitations warrant little, if any, range of equivalents.” ….

Turning to the case before it, the Federal Circuit stated:

The claimed process operates by using a pressurized collection vessel wherein dispersion accumulates to maintain backpressure in the extruder. To state it differently, it is the accumulation of dispersion in the collection vessel that generates the backpressure. Dow’s accused process, on the other hand, “uses a valve” and does not allow for accumulation in the downstream pipes. …. Thus, in order to survive summary judgment, Akzo had to show that a valve and a series of pipes and heat exchangers, wherein the dispersion flows continuously, generate backpressure in the extruder in substantially the same way to increase the boiling point of the carrier fluid. It did not do so.

The Federal Circuit cited the following expert testimony relied upon by Akzo:

Dow’s and Michelman’s piping and heat exchangers perform the same function (maintain the pressure) and achieve the same result (maintaining sufficient pressure to prevent boiling of the aqueous medium) in substantially the same way (by collecting the dispersed material in a contained volume) as the vessel used by the inventors in Examples 2 and 3 of the patent. J.A. 1100–01.

In addition to criticizing this testimony for being “broad and scant,” the court found that “what truly undermines Akzo’s reliance on the above-quoted statement is the statement’s failure to articulate how Dow’s accused process operates in substantially the same way.” Moreover, given the claim construction dispute over the “collection” vessel, the court found it significant that “Dr. Mount … fails to articulate which construction of “collecting” he invokes, much less articulate how the differences between the two processes are insubstantial.” Concluding that “[s]uch ambiguity and generality cannot create a genuine issue of material fact,” the Federal Circuit affirmed the district court’s grant of summary judgment. 

Scrutiny Of The Evidence

In addition to shedding light (or not) on what is required to establish infringement under the doctrine of equivalents, this decision illustrates the scrutiny that the Federal Circuit may apply to expert testimony. For example, the court noted that the testimony at issue came “in the last paragraph of a fifty-one paragraph declaration,” was “broad and scant,” “fail[ed] to articulate how [the] accused process operates in substantially the same way,” and failed to “articulate how the differences … [were] insubstantial.” While it is not possible to avoid providing some testimony “in the last paragraph,” it is clear that the court was expecting a more rigorous analysis under each prong of the function-way-result test for each element alleged to be infringed under the doctrine of equivalents.