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Judge Andrews Construes Terms of Patent-In-Suit, Finding Preamble Limiting and Deferring Decision on Indefiniteness

Judge Andrews recently issued a claim construction opinion in a case between DuPont and Unifrax involving “composite flame barrier laminate for thermal and acoustic blankets used in aircraft structures.” E.I. DuPont de Nemours & Co. v. Unifrax I LLC, C.A. No. 14-1250-RGA, Memo. Op. at 2 (D. Del. Jan. 13, 2016). Among various disputed constructions, two issues are of particular interest. First, the parties disputed whether the term “laminate,” which appears in the preamble of claim 1 of the patent-in-suit, should be seen as limiting. Judge Andrews found that “laminate” is in fact limiting because it “gives ‘life, meaning, and vitality’ to the claim and imparts a structure that is not present in the recitation of the layers in the body of the claim. The patent repeatedly refers to the invention as a laminate [and the] claim body does not disclose a complete structure.” Id. at 4-6.

Second, the parties disputed whether the phrase “wherein the inorganic refractory layer of (iii) comprises platelets in an amount of 100% by weight with a dry areal weight of 15 to 50 gsm and a residual moisture content of no greater than 10 percent by weight” rendered the claim at issue indefinite. Judge Andrews decided that the indefiniteness dispute was not suitable for resolution at the claim construction stage: “That the claim admittedly does not set forth a requirement with respect to what percent of the refractory layer must constitute platelets or what the total weight of the layer is may make the claim broad. It does not, however, make the claim internally inconsistent. Additional evidence would be necessary to determine whether the claim informs one of skill in the art, with reasonable certainty, about the scope of the invention. Whether the disputed term renders the claim indefinite is therefore not amenable to resolution at this time.” Id. at 24-27.

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