Mid 1980s, if I recall correctly. Another one of EK's disasters--infringing on another company's patents.
Before releasing the product, Kodak hired a group of prominent attorneys to evaluate this very thing. The consensus was that Kodak would not infringe any existing Polaroid patent. The judge ruled otherwise. But, because of this effort, he was unable to find Kodak guilty of any malicious intent to defraud Polaroid or any intent to harm Polaroid and so damages were quite minimal compared to what they would have been otherwise.