Panel Puts Out Appeal in Firefighter Fabric Case

(CN) - Polartec's fire-resistant fabric for firefighter suits does not infringe on a patent for a similar material created by Georgia-based manufacturer Southern Mills, the Federal Circuit ruled.

The appellate panel in Washington, D.C., ruled that Polartec's fabric differs from Southern Mills' in that it has a "3-end knit" that requires the use of three different yarns.

A federal judge in Georgia had ruled for Polartec, and the parties agreed that Southern Mills could not prove infringement based on the court's interpretation of the patent claims.

Southern Mills consented to a judgment of non-infringement so that it could challenge the district court's claim constructions.

It argued on appeal that Polartec's "3-end knit" does not require the use of three different yarns, only yarns capable of serving three different functions. The use of three separate yarns, Southern Mills claimed, was only the "preferred embodiment."

The federal appeals court disagreed.

"While it is true that the yarns must perform those three functions, it is also evident from the specification that those three functions are performed by three different yarns," Judge William Bryson wrote.

However, the three-judge panel disagreed with the lower court's interpretation of the patent claim for "a fleece knit thermal barrier fabric." The district court incorrectly limited that claim to fabrics "having three different yarns," even though the fabric has only two yarns, the panel ruled.

"Because we disagree with the district court's construction of the term 'tie yarns' ... and because the parties agreed to a consent judgment based on the court's claim construction order, we reverse the judgment with respect to [the thermal barrier fleece] and its asserted dependent claims," the court wrote.

It otherwise upheld the ruling for Polartec.

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