E.I. Du Pont De Nemours & Co. v. Unifrax I LLC
921 F.3d 1060
Fed. Cir.2019Background
- DuPont’s U.S. Patent No. 8,607,926 claims a three-layer composite laminate (polymeric film, adhesive, inorganic refractory layer of vermiculite platelets) for aircraft flame barriers; claim 1 requires the refractory layer to “comprise platelets in an amount of 100% by weight” with a dry areal weight of 15–50 gsm and residual moisture ≤10% by weight.
- The ’926 patent issued from a continuation‑in‑part of an earlier DuPont patent (the ’027 patent) that described a 100% platelet layer and expressly stated there may be residual dispersant from incomplete drying and that no carrier (resin, adhesive, cloth, paper) is present in the 100% platelet embodiment.
- During prosecution DuPont amended claims to recite “100% by weight” platelets to overcome prior art (Tompkins) that disclosed lower platelet concentrations, resulting in a disclaimer of embodiments with less than 100% platelets relative to carrier material.
- Unifrax’s accused product (Combi‑Film 3G11) contains a vermiculite refractory layer made from a dispersion including vermiculite, DEHESIVE 480 (contains PDMS), tetrasodium pyrophosphate (TSPP, a dispersant), and water; dispute focused on whether DEHESIVE 480 or silane in the product are “carrier” materials that exclude literal infringement.
- District court construed “100% by weight” to mean: no carrier material (resin, adhesive, cloth, paper) in addition to platelets, but permitting some residual dispersant from incomplete drying; a jury found infringement and no invalidity; Unifrax moved for JMOL on non‑infringement and invalidity and lost.
- On appeal the Federal Circuit affirmed the claim construction and the denial of JMOL, finding (1) intrinsic evidence (claims, specification, parent ’027 patent, and prosecution history) supports construing 100% relative to carrier material and permitting residual dispersant/moisture, and (2) substantial evidence supported the jury’s findings that DEHESIVE 480 was not a carrier and that silane did not function as a carrier or was not in the refractory layer, and that prior art (Mormont) and Unifrax’s 3G7 product did not anticipate the asserted claims.
Issues
| Issue | Plaintiff's Argument (DuPont) | Defendant's Argument (Unifrax) | Held |
|---|---|---|---|
| Proper construction of “100% by weight” in claim 1 | Term should be read in context: 100% is relative to carrier material; specification and parent patent allow residual dispersant/moisture; no carrier (resin/adhesive/cloth/paper) in 100% embodiment | Plain meaning: “100%” means literally 100%, excluding any other ingredients (except trivial impurities); no need to import parent patent language about carriers | Court affirmed construction: 100% means platelets constitute 100% relative to carrier materials (no carrier such as resin/adhesive/cloth/paper) but permits residual dispersant/moisture from incomplete drying. |
| Literal infringement (whether Combi‑Film 3G11 meets the 100% limitation) | DEHESIVE 480 (PDMS) and silane in Unifrax product are not carriers/binders in the vermiculite layer; evidence supports that PDMS here is a release agent and no crosslinker is present; silane is an overlayer or not present in refractory layer | DEHESIVE 480 (PDMS) functions as an adhesive/carrier; silane impregnates the refractory layer and acts as a carrier — so the refractory layer is not 100% platelets by weight | Affirmed: substantial evidence supported jury verdict of infringement because DEHESIVE 480 was not shown to be a carrier and silane was not shown to be in or to function as a carrier in the refractory layer. |
| Anticipation by Mormont prior art | Mormont does not disclose the same refractory construction because its methyl‑silicone (Wacker K) functions as a binder/resin (5–25% binder) and differs from the PDMS release agent in Combi‑Film | Mormont’s Example discloses a methyl silicone binder (Wacker K) in the refractory layer that anticipates the claimed refractory layer | Affirmed: substantial evidence supported jury verdict that Mormont did not anticipate the asserted claims. |
| Antedating Unifrax’s product 3G7 (priority/earlier conception & reduction to practice) | DuPont presented corroborated inventor testimony and documentary evidence (emails, test reports, FAA August 2010 tests) showing conception and reduction to practice before May 17, 2011 public use of 3G7 | Unifrax argued that 3G7 was prior public use that anticipates; contended documentary evidence did not independently show claimed ranges | Affirmed: applying the rule‑of‑reason, substantial corroborating evidence supported inventors’ testimony and the jury’s finding that DuPont’s priority antedated 3G7. |
Key Cases Cited
- Markman v. Westview Instruments, 517 U.S. 370 (1996) (claim construction is a question of law for the court)
- Phillips v. AWH Corp., 415 F.3d 1303 (Fed. Cir. 2005) (claims construed in view of specification and prosecution history)
- Vitronics Corp. v. Conceptronic, Inc., 90 F.3d 1576 (Fed. Cir. 1996) (primacy of intrinsic evidence in claim construction)
- CardSoft, LLC v. VeriFone, Inc., 807 F.3d 1346 (Fed. Cir. 2015) (review standards for claim construction and related factual findings)
- Becton, Dickinson & Co. v. Tyco Healthcare Grp., LP, 616 F.3d 1249 (Fed. Cir. 2010) (standard for JMOL reviewing sufficiency of evidence)
- ACCO Brands, Inc. v. ABA Locks Mfrs. Co., 501 F.3d 1307 (Fed. Cir. 2007) (infringement tried to a jury reviewed for substantial evidence)
- TI Grp. Auto. Sys. (N. Am.), Inc. v. VDO N. Am., L.L.C., 375 F.3d 1126 (Fed. Cir. 2004) (anticipation as factual question reviewed for substantial evidence)
- NFC Tech., LLC v. Matal, 871 F.3d 1367 (Fed. Cir. 2017) (inventor testimony corroboration treated as question of fact)
- Price v. Symsek, 988 F.2d 1187 (Fed. Cir. 1993) (priority rules: first to reduce to practice unless earlier conception with diligence)