## Facts

- Dow asserted three patents on non-CFC polyethylene foam technology using isobutane as a blowing agent: U.S. Patent Nos. 4,640,933, 4,694,027, and 4,663,361.
- Dow sued Astro-Valcour, Inc. (AVI) for infringement in the Northern District of New York.
- AVI defended by alleging invalidity under 35 U.S.C. § 102(g), claiming it conceived and reduced to practice the claimed subject matter before Dow.
- AVI began experimenting in March 1984 using a known process and, by the end of that month, produced commercial-quality polyethylene foam using isobutane.
- AVI did not initially treat its work as a patentable invention and did not file its own patent application.
- AVI built production capacity and began selling isobutane-blown polyethylene foam publicly in the latter half of 1986.
- Dow reduced its process to practice by September 1984 and filed its patent application in December 1985.
- After trial, the district court found AVI was the prior inventor and had not abandoned, suppressed, or concealed the invention, and it invalidated claim 3 of the ’933 patent, claim 1 of the ’027 patent, and claim 1 of the ’361 patent.
- Dow appealed.

## Issues

1. Whether a party asserting prior invention under 35 U.S.C. § 102(g) must have known it was an inventor or appreciated the patentable nature of its work.
2. Whether AVI, even if first to invent, lost § 102(g) priority by abandoning, suppressing, or concealing the invention due to not filing a patent application and delaying public disclosure until commercialization.

## Decision

- The Federal Circuit affirmed the judgment.
- A § 102(g) prior inventor need not know it is an inventor or recognize the work as patentable.
- Substantial evidence supported that AVI conceived and actually reduced to practice the subject matter of the contested claims before Dow.
- AVI did not abandon, suppress, or conceal the invention; the time spent scaling to commercial production and later public sales did not establish disqualifying concealment.
- The asserted claims were invalid: claim 3 of the ’933 patent, claim 1 of the ’027 patent, and claim 1 of the ’361 patent.

## Legal Principles

- Under pre-AIA 35 U.S.C. § 102(g), priority turns on objective proof of conception and reduction to practice, not on subjective awareness of inventorship or patentability.
- Abandonment, suppression, or concealment can be shown by active concealment or inferred from unreasonable delay in making the invention publicly known.
- Failure to file a patent application, by itself, does not establish abandonment, suppression, or concealment where the record shows reasonable efforts toward commercialization followed by public disclosure through commercial use.

## Conclusion

The Federal Circuit held that § 102(g) does not impose a “knowledge of inventorship” requirement and affirmed invalidity of Dow’s asserted claims because AVI proved earlier conception and reduction to practice and did not abandon, suppress, or conceal its invention despite not seeking a patent and taking time to commercialize.


Dow Chem. Co. v. Astro-Valcour, Inc., 267 F.3d 1334 (Fed. Cir. 2001)