It is important to establish the “criticality” of a claimed range to the claimed invention in order to avoid anticipation by a prior art reference disclosing a broader, overlapping range. Here, for example, a lubricant claimed in the amount of 0.05 to 0.5% by weight was found to be anticipated by a prior art reference disclosing a range of .1 to 5, even though the narrower claimed range better avoided cost and prevented undesirable blemishes, because these advantages had nothing to do with the touted operability or functionality of the claimed invention. It may therefore be best to include in the specification a discussion about how values outside of a claimed range would provide reduced if not inoperable functionality.

Background / Facts: The patent being asserted here is directed to polyethylene-based compositions which can be used to form shaped products, such as screw caps for bottles. The claims recite compositions having specific amounts of polyethylene, lubricants, and additives, including what the court refers to as limitation 2, “0.05 to 0.5% by weight of at least one saturated fatty acid amide” lubricant. The prior art discloses a similar lubricant but in amounts over a much broader range, from 0.1 to 5 parts by weight.

Issue(s): Whether the prior art’s substantially broader range disclosure anticipates the narrower claimed range.

Holding(s): Yes. “The [district] court’s conclusion that limitation 2 was met by the [prior art] was correct because [the patentee] did not raise a genuine question of fact about whether the range recited in limitation 2 is critical to the invention. The [] patent specification indicates that the lubricants included in the invention function to improve the caps’ slip properties and ability to be unscrewed from a bottle. [] It then describes the novelty of the invention as eliminating the odor and taste problems associated with prior art bottle caps while still maintaining good slip properties. [] [The patentee] has not established that any of these properties would differ if the range from the prior art [] is substituted for the range of limitation 2.”

Full Opinion