Viskase Corp. v. American National Can Co.

• Citation: 59 USPQ2d 1823,261 F.3d 1316
• Decision Date: 31 July 2001
• Docket Number: -1570,PLAINTIFF-APPELLEE,No. 99-1569,DEFENDANT-APPELLANT,99-1569
• Parties: (Fed. Cir. 2001) VISKASE CORPORATION,, v. AMERICAN NATIONAL CAN COMPANY,
• Court: United States Courts of Appeals. United States Court of Appeals for the Federal Circuit

Page 1316

261 F.3d 1316 (Fed. Cir. 2001)

VISKASE CORPORATION, PLAINTIFF-APPELLEE, v. AMERICAN NATIONAL CAN COMPANY, DEFENDANT-APPELLANT.

No. 99-1569, -1570

United States Court of Appeals for the Federal Circuit

July 31, 2001

Appealed from: U.S. District Court for the Northern District of Illinois

[Copyrighted Material Omitted]

[Copyrighted Material Omitted] Roy E. Hofer, Brinks Hofer Gilson & Lione, of Chicago, Illinois, argued for plaintiff-appellee. With him on the brief were Allan J. Sternstein, William H. Frankel, and Andrew D. Stover. Of counsel on the brief were Philip S. Beck and Chris J. Lind, Bartlit Beck Herman Palenchar & Scott, of Chicago, Illinois; and Joseph v. Colaianni, Patton Boggs, L.L.P., of Washington, Dc. James R. Atwood, Covington & Burling, of Washington, DC, argued for defendant-appellant. With him on the brief were Timothy C. Hester, Thomas W. Krause, and Glen D. Weinstein. Of counsel on the brief was James F. Davis, Howrey & Simon, of Washington, Dc.

Before Newman, Lourie, and Rader, Circuit Judges.

Newman, Circuit Judge.

Judge Elaine E. Bucklo

This patent infringement suit concerns six patents owned by Viskase Corporation on heat-shrinkable films and their use to make plastic bags for packaging food articles. Viskase charged American National Can Company (ANC) with infringement. The district court held a Markman hearing, construed the claims, decided various motions for summary judgment, held a jury trial, conducted post-trial proceedings, entered judgment that the patents were valid and willfully infringed by ANC, and awarded damages. ¹ The court denied motions brought under Federal Rules of Civil Procedure 50(b), 59, and 60. This appeal followed. We affirm in part, reverse in part, and remand for further proceedings.

The Patented Inventions

The patents in suit relate to heat-shrinkable multilayer thermoplastic compositions having very low density polyethylene copolymers (VLDPE) in biaxially stretched outer layers, and core layers of various vinyl plastics as oxygen barriers, typically a copolymer of vinylidene chloride or an ethylene/vinyl alcohol copolymer. The "first family" patents, as the parties and the district court call them, are United States Patents Nos. 4,863,769; 4,976,898; 5,059,481; and 5,256,351; all relate to outer film layers of VLDPE having specific density limits and other parameters. Claim 33 of the '769 patent is illustrative, with emphases added to the aspects of concern in this litigation:

33. A heat-shrinkable, puncture resistant, biaxially stretched, thermoplastic film suitable for use in fabricating bags for packaging food articles such as frozen poultry, said film comprising a very low density polyethylene which is a linear copolymer of ethylene and higher alpha olefin containing from 3 to 8 carbon atoms, having a density below about 0.91 g/cm3, a 1% secant modulus below about 140,000 kPa, and said film being formed using a double bubble method and wherein said film heat-shrinks from about 30 percent to about 50 percent at a temperature of about 90E C. in the transverse direction.

The "second family" patents relating to heat-shrinkable films, United States Patent Nos. 4,863,784 and 4,988,465, also use VLDPE in the outer layers of a multilayer thermoplastic film, and as the core layer a copolymer of vinylidene chloride and methyl acrylate (MA-saran). Claim 1 of the '784 patent is illustrative (with emphases added):

1. A coextruded, thermoplastic, heat shrinkable, multilayer film wherein:

(a) said multilayer film comprises a first layer comprising very low density polyethylene of density not greater than about 0.915 grams per cubic centimeter, a core layer comprising vinylidene chloride-methyl acrylate copolymer . . . and a second layer comprising very low density polyethylene of density not greater than about 0.915 grams per cubic centimeter; and

(b) said first layer is adhered directly to one side of said core layer without adhesive material there between and said second layer is adhered directly to the other side of said core layer without adhesive material there between.

The dispute as to infringement turns on the scope of the densities of VLDPE encompassed in "below about 0.91 g/cm3" for the first family patents and "not greater than about 0.915 g/cm3" for the second family patents, and the degree of branching of the VLDPE. Also on appeal are questions of validity and related issues.

I. CLAIM CONSTRUCTION

The ANC heat-shrinkable films at issue have a MA-saran core and either a linear ethylene copolymer having a density of 0.912 g/cm3 (a product of the Dow Chemical Company having the brand name "Attane"), or an ethylene copolymer having a density of 0.908 g/cm3 whose linear/branched structure was disputed (a Dow product having the brand name "Affinity").

"Density" - The First Family

The district court construed the density term "about 0.91 g/cm3" to mean densities between 0.905 and 0.914, based on the reasoning that numbers in this range would be rounded to 0.91. We agree that this is a standard scientific convention when a number has not been carried to the next mathematically significant figure. However, ANC disputes the applicability of this convention to the facts of this case.

ANC argues that the specification and prosecution history make clear that "below about 0.91 g/cm3" is not entitled to broader scope than "below about 0.910 g/cm3", citing conventional descriptions of the densities of various classes of polyethylenes. ANC states that 0.91 g/cm3 is a generally accepted dividing line between "very low" and "low" density polyethylenes, and that a density range of the breadth adopted by the district court is contrary to this accepted usage, for it takes "very low density" into the range of "linear low density." ANC points out that during prosecution of the first family patents Viskase used 0.91 with a zero in the third decimal place. ANC also cites Viskase's incorporation into the first family patents of the process descriptions in commonly owned United States Patent No. 4,302,566 (Karol), which designated 0.91 g/cm3 as the upper boundary for very low density polyethylenes. The first family '769 patent states that Karol teaches that:

In order to produce ethylene copolymers having a density below 0.91 g/cm3 by means of a fluid bed process, it is necessary to employ gaseous reaction mixtures containing higher amounts of higher alpha olefin comonomer vis-a-vis the amount of ethylene employed, than are employed to produce copolymers having a density of greater than 0.91 g/cm3.

'769 patent, col. 2, lines 53-59. Another patent referenced in the first family specifications, United States Patent No. 4,302,565 (Goeke), contains a similar process description. ANC argues that these usages of "below 0.91" and "greater than 0.91" are meaningless if 0.91 g/cm3 were intended to have a range as high as the 0.914 g/cm3 holding of the district court. Thus ANC argues that a scope significantly higher than 0.910 g/cm3 is not a reasonable construction of the usage "below about 0.91" in the claims of the first family.

Viskase disagrees, and points out that the second family '784 patent, filed one month after filing of the '769 application, defines "very low density" as reaching to "about 0.915 g/cm3":

[T]hose copolymers having a density in the range of from about 0.86 to about 0.915 grams per cubic centimeter are commonly referred to as a very low density polyethylene, while those having a density greater than about 0.915 grams per cubic centimeter are commonly referred to as linear low density polyethylene.

'784 patent, col. 9, lines 14-20. Viskase states that the scientific literature accepts this higher figure, and that in all events the inventors made clear the definition they intended. ANC responds with other sources that draw a line at 0.910, citing Ferguson Patent No. 4,640,856, filed in 1985, which defines very low density polyethylenes as having a density "of less than 0.910 [while] conventional polyethylenes and LLDPEs [linear low density polyethylenes] have densities as low as 0.912."

ANC stresses that during prosecution of the first family, Viskase itself treated 0.91 as if it were 0.910. In discussing Shibata United States Patent No. 4,429,079 when Viskase cited this reference to the patent examiner, Viskase recognized that Shibata describes a multilayer heat-shrinkable composition using a linear low density polyethylene copolymer (Shibata's "A" copolymer) having a density range of "0.910 to 0.940 g/cm3." Viskase distinguished its products from Shibata by stating:

The "A" copolymer is clearly not pertinent to the present application in that it does not have a density below about 0.910 g/cm3 as defined in all pending claims.

We agree with ANC that this statement is highly relevant, for it relies on the third significant figure of the 0.910 g/cm3 density to distinguish the first family densities, claimed as "below about 0.91 g/cm3," from the prior art densities of 0.910 to 0.940 g/cm3.

Viskase states that its use of 0.910 in distinguishing the first family from the Shibata product was an error by its patent attorney, and points out that 0.910 does not appear in any of the first family specifications or claims or elsewhere in the prosecution history. An asserted error in the prosecution record must be viewed as are errors in documents in general; that is, would it have been apparent to a person experienced in this technology that an error was made, or at least that the information should not be relied upon. See Biotec Biologische Naturverpackungen GmbH & Co. v. Biocorp, Inc., 249 F.3d 1341, 1348, 58 USPQ2d 1737, 1742-43 (Fed. Cir. 2001). The district court agreed with Viskase, and ruled that this isolated usage of the density figure 0.910 did not outweigh the extensive usages of 0.91 in the first family patents. The court declined to construe "below about 0.91 g/cm3" as meaning below 0.910 g/cm3 or below about 0.910 g/cm3.

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