Nike's Flyknit technology has been one of the most popular modern innovations in footwear since its debut five years ago. Adidas launched its own version of knitted uppers with the introduction of Primeknit. Despite both brands having success with their respective innovations, Adidas is continuing its battle with Nike regarding the patentability of Flyknit that began back in 2012 when Nike attempted to halt Adidas' production of Primeknit footwear altogether.

According to Portland Business Journal, Adidas filed with the U.S. Federal Court of Appeals regarding a decision this past October by the Patent Trial and Appeal Board upholding Nike's Flyknit patent this past Thursday. The "749 Patent" was granted back in 2004, and gave Nike ownership of the Flyknit's one-piece yarn upper construction, and its accompanying methods of manufacturing.

Adidas is claiming that this is unpatentable because although this process was not previously used to create footwear, it was already a "conventional" textile process to create other items. This claim is based off of Title 35, Section 103 of U.S. patent law, which says a patent cannot be claimed if the invention, "would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains."

This is just the latest in a string of battles between the two footwear juggernauts, both in and out of the courtroom