[T]he transitional phrase “consisting of” does not necessarily suggest that a Markush group is closed to mixtures, combinations, or blends.
Multilayer Stretch Cling Film Holdings, Inc. v. Berry Plastics Corp. (Fed. Cir. Aug. 4, 2016) (Before Dyk, Plager, and Taranto, J.) (Opinion for the court, Dyk, J.) Click Here for a copy of the opinion.
In an August 4, 2016 opinion, a split Federal Circuit reversed in part a district court’s construction of a cling-film patent’s Markush group claim element, and vacated summary judgment of non-infringement predicated on that construction. Multilayer Stretch Cling Film Holdings (“Multilayer”) brought suit against Berry Plastics Corp. (“Berry”), alleging infringement of U.S. Patent No. 6,265,055, which is directed toward multi-layered plastic cling wrap films. The asserted cling-film claim recites “five identifiable inner layers with each layer being selected from the group consisting of LLDPE, VLDPE, ULDPE, and mLLDPE resins.” The district court held on summary judgment that Berry’s products did not infringe because the inner layers of Berry’s films consisted of blends of resins, and therefore did not meet the asserted patent’s closed Markush group limitation. More specifically, the court analyzed the “consisting of” language used to define the group, and held that in order to encompass additional resins, the claim should have been written to include the word “comprising.”
Multilayer appealed the judgment, asserting that the district court erred in its claim construction, and that “[t]he intrinsic evidence clearly establishes that the Markush groups in claims 1 and 28 should be construed as open” to other resins. On appeal, the Federal Circuit first recognized that “consisting of,” is a term of art in patent law with a distinct and well-established meaning. Use of the transitional phrase “consisting of” to set off a patent claim element creates a very strong presumption that that claim element is “closed” and therefore “exclude[s] any elements, steps, or ingredients not specified in the claim.” AFG Indus., Inc. v. Cardinal IG Co., Inc., 239 F.3d 1239, 1245 (Fed. Cir. 2001). The Court concluded that limited intrinsic evidence identified by Multilayer was insufficient to overcome the very strong presumption, created by the patent’s use of the transitional phrase “consisting of,” that the Markush group was closed to resins other than the four recited: LLDPE, VLDPE, ULDPE, and mLLDPE.
However, in spite of the Court’s determination that the Markush group was closed, the Court agreed with Multilayer that the use of the transitional phrase “consisting of” does not necessarily suggest that a Markush group is closed to mixtures, combinations, or blends. Although recognizing that, typically, there exists a presumption that Markush groups are closed to “blends,” the Court acknowledged that the presumption can be overcome by a combination of other claim language and the specification itself. Here, the Court found explicit evidence of an intent to include blends insofar as the Markush group itself included blends and categories of resins that overlap, and certain dependent claims required layers of film to comprise blends of at least two resins. Thus, the Court found that a layer could still “consist” of the listed resins even if the layer “consists” of a mixture of those resins.
Lindsay Henner, Parker Hancock, and Puja Dave also contributed to this summary.