Tenneco Chemicals, Inc. v. William T. Burnett & Co., Inc., and Reeves Brothers, Inc.

CHAPMAN, Circuit Judge:

Appellant Tenneco Chemicals, Inc. brought this action for infringement of its patents by appellees, Reeves Brothers, Inc., and William T. Burnett, Inc. Appellees counterclaimed seeking to declare Tenneco’s patents invalid. The district court, at the close of Tenneco’s case in chief, granted appellees’ motion for involuntary dismissal on the merits, declaring two of the Tenneco patents invalid; a third patent was held not infringed. We affirm in part and reverse and remand in part.

I

Prior to the development of the inventions involved in this case, polyurethane foam had…