Expert Testimony Based on Modified Claim Construction Precluded

The court granted in part plaintiff's motion in limine to preclude expert testimony premised on a revised construction of the claim term in question. "⁠[T]he court [previously] construed the claim term 'intumescent' to describe 'a substance that swells and chars upon exposure to heat or flame.' . . . [O]ver three years after the claim construction . . . [defendant] seeks to offer evidence from one of ordinary skill in the art that infringement of the claim term 'intumescent' requires proof that the coating 'swells to a sufficient degree to act as a thermal barrier to lessen the effects of heat or flame on the underlying fabric.' . . . [T]he court declines to further define the term 'swell.' . . . [Defendant] should be permitted to present evidence by an expert as to whether he observes any swelling . . . and criticisms of [plaintiff's] expert’s findings. . . . [H]e may not testify as to any opinion that the results reportedly observed by [plaintiff's expert] fail to indicate swelling 'to a sufficient degree to act as a thermal barrier to lessen the effects of heat or flame on the underlying fabric' because he has conducted no testing to support such a statement."

Precision Fabrics Group, Inc. v. Tietex International, Ltd., 7-17-cv-03037 (SCD March 5, 2018, Order) (Schroeder, USDJ)