Industrial gas producer Praxair Inc.have announced an appeals court has upheld an earlier ruling that a competitor's patents were invalid.

The U.S. Court of Appeals for the Federal Circuit upheld an April 2006 decision by a New York federal court that some patents held by ATMI, which provides specialty materials to semiconductor makers, were invalid.

That same lower court also dismissed ATMI's patent infringement case against Praxair. Praxair is still seeking damages against ATMI in a separate case in which ATMI's technology was held to violate Praxair's patents.

Shares of Praxair rose 46 cents in midday trading on the New York Stock Exchange.