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Claim Construction Affirmed, but Remand on Infringement

04-1246
April 11, 2005
Wang, Ningling

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Last Month at the Federal Circuit - May 2005

Judges: Gajarsa (author), Newman, and Clevenger

In Rhodia Chimie v. PPG Industries Inc., No. 04-1246 (Fed. Cir. Apr. 11, 2005), the Federal Circuit affirmed-in-part and reversed-in-part the district court’s SJ in favor of PPG Industries, Inc. (“PPG”), and remanded on infringement because the evidence before the court created a genuine issue of material fact regarding one of PPG’s accused products.

Rhodia Chimie and Rhodia Inc. (collectively “Rhodia”) are the assignees of U.S. Patent No. 6,013,234 (“the ’234 patent”), which discloses and claims certain essentially spheroidal precipitated silica particulates and processes of manufacturing those particulates. The sole claim at issue contains the disputed terms “dust-free and non-dusting” and “atomized precipitated silica particulate.” Rhodia identified three silica products made by PPG, i.e.,Hi-Sil SC60M, SC72, and SC72C, that allegedly infringe claim 1 of the ’234 patent, and sued PPG for willful infringement.

The Federal Circuit affirmed the district court’s construction of the disputed term “dust-free and non-dusting” to mean “a level of dust formation associated with the silica particulates of the ’234 patent, as measured in percentage weight according to DIN 53 583, that has a fines content value of less than or equal to 13 and weight loss by abrasion value less than or equal to 0.5.” “DIN 53 583” is an industrial standard that provides a test for measuring the fines content and weight loss by abrasion of palletized carbon black used as fillers in the rubber-processing industry (the “DIN test”).

The Federal Circuit reasoned that the term “dust-free and non-dusting” could not be read literally to mean that the invention creates no silica dust at all, as advocated by PPG, because the test results disclosed in the written description indicate that the invention itself produces some dust, but less dust than the prior art. The Court also noted that the term “dust-free and non-dusting” could not be construed to mean that the level of dust “is very low when compared to other silica forms,” as advocated by Rhodia, because such a definition is “a relative phrase,” which can only be understood in comparison to the prior art. Instead, the Federal Circuit looked at the written description of the ’234 patent, specifically, the ten examples disclosed therein, and determined that referring to the DIN test in defining the term “dust-free and nondusting” reconciles the ambiguous claim language with the inventor’s disclosure.

Rhodia challenged this claim construction on the ground that the DIN test is not the only method by which to assess the amount of dust produced by the invention in comparison to the prior art. Rhodia argued that the pour test disclosed in the specification could also be used to assess the amount of dust, relying on the statements made during the prosecution of the patent showing that the pictures of the pour test were cited as evidence of the nondusting and free-flowing properties. However, the Federal Circuit held that because neither the claims nor the written description teaches the use of the pour test to determine the level of dust production claimed by the invention, the statements made during the prosecution of the ‘234 patent could not serve to fill that gap.

The Federal Circuit also affirmed the district court’s construction of the disputed term “atomized precipitated silica particulates” to mean “that a pulverized slurry of precipitated silica is spray dried using a liquid pressure nozzle as an atomizer to form the claimed silica particulates,” in view of the prosecution history, where Rhodia distinguished the prior art by emphasizing that its claimed silica particulates could be obtained only by applying liquid-pressure nozzle sprayers to a pulverized slurry.

Rhodia further challenged the district court’s decision of no literal infringement on two grounds: (1) the district court abused its discretion in excluding Rhodia’s DIN testing evidence on PPG’s accused products; and (2) even without the excluded DIN test results, the evidence provided by PPG showing that PPG’s own DIN testing results for one of the accused products, i.e., SC60M, fall within the range established by the district court’s claim construction raised a genuine issue of material fact as to literal infringement.

The Federal Circuit held that the district court did not abuse its discretion in excluding Rhodia’s DIN testing results under Third Circuit law, because it was unreasonable for Rhodia to delay investigation into DIN testing until after the issuance of the claim-construction opinion.

As to Rhodia’s second evidentiary ground in challenging the district court’s decision of no literal infringement, PPG argued that the evidence on its DIN testing results for SC60M was irrelevant because the results were produced prior to the issuance of the ’234 patent and Rhodia produced no evidence linking the sample tested to PPG’s postissuance commercial practices. The Federal Circuit rejected PPG’s arguments and reemphasized that evidence regarding preissuance activities may be relevant to establishing that postissuance products constitute infringement. Therefore, the Court concluded that the evidence on PPG’s own DIN testing results for SC60M created a genuine issue of material fact as to whether the postissuance form of SC60M literally infringes the ’234 patent.

Finally, the Federal Circuit affirmed the district court’s decision of noninfringement under the DOE because of prosecution history estoppel, as Rhodia made narrowing amendments in the prosecution of the patent to overcome prior art rejections.