## Facts

- A licensee and an intervenor asserted infringement of a patent and reissue patent claiming blasting compositions combining an unsensitized water-in-oil emulsion with a substantially undissolved particulate oxidizer salt (e.g., ammonium nitrate), in specified proportions.
- The claims required “sufficient aeration” (entrapped gas/air) to enhance the composition’s sensitivity to detonation.
- The accused products were commercial explosive compositions sold by the defendants.
- The defendants relied on two prior art references disclosing ANFO/emulsion-type blasting compositions with ingredients and proportions overlapping the claimed ranges.
- After two bench trials, the district court found the asserted claims invalid as anticipated by the prior art and also found no infringement.
- The plaintiffs appealed to the Federal Circuit.

## Issues

1. Whether the asserted claims were anticipated under 35 U.S.C. § 102 because the prior art disclosed every limitation, including the “sufficient aeration” limitation, expressly or inherently.
2. How to construe the “sufficient aeration … entrapped to enhance sensitivity to a substantial degree” limitation, including whether it covers both interstitial and porous air.
3. Whether the accused products infringed any asserted claim if valid.

## Decision

- The Federal Circuit affirmed the judgment that the original patent and reissue patent were invalid as anticipated by the prior art.
- The court agreed that the “sufficient aeration” limitation encompassed both interstitial air and porous air.
- Based on the district court’s factual findings (including testing and expert testimony), the court held that practicing the prior art within the overlapping composition ranges necessarily produced sufficient aeration; the limitation was therefore inherently disclosed.
- The court left undisturbed the district court’s non-infringement determination.

## Legal Principles

- A claim is anticipated if a single prior art reference discloses every claim limitation either expressly or inherently.
- Inherent anticipation applies when the missing limitation is necessarily present (inevitable) when practicing the prior art; prior recognition or discussion of the inherent characteristic is not required.
- Overlapping ranges between claimed compositions and prior art compositions can support anticipation when practicing within the overlap necessarily yields the claimed property.
- Functional claim language (e.g., requiring a composition to achieve a stated performance) does not avoid anticipation if the function necessarily results from the prior art disclosure.

## Conclusion

The Federal Circuit affirmed invalidity because the prior art compositions, made within overlapping ingredient ranges, necessarily contained the entrapped air required for “sufficient aeration,” so the claimed sensitivity feature was inherently anticipated; the non-infringement judgment remained in place.


Atlas Powder Co. v. Ireco Inc., 190 F.3d 1342 (Fed. Cir. 1999)