Patent Law Practice Center

Federal Circuit Affirms District Court on Infringement and Definiteness in Dow Chemical Case

On January 29, 2016, the United States Court of Appeals issued a decision in AKZO Nobel Coatings, Inc. v. Dow Chemical Company, relating to an appeal from the United States District Court for the District of Delaware.

Akzo appealed from the district court’s granting of summary judgment that Dow did not infringe the claims of U.S. Patent 6,767,956, either literally or under the doctrine of equivalents. Dow cross-appealed from the court’s conclusion that the claims of the ’956 patent are not indefinite.

Claim 1 of the ‘956 patent was deemed representative and reads as follows:

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 100° C. 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 100° C. to have an aqueous dispersion with a viscosity below 10 Pa.s.

(more…)