3M and a British private-equity firm have been trading barbs publicly about a product that 3M decided not to commercialize. Here are the latest: http://finance.yahoo.com/news/3M-Responds-to-Accusations-bw-3785196144.html?x=0&.v=1 http://finance.yahoo.com/news/Porton-Group-Slams-3Ms-prnews-447673034.html?x=0&.v=1