Patent Appeal No. 76-577. February 24, 1977. Rehearing Denied April 28, 1977. Eugene Sabol, Fisher, Christen Sabol, Washington, D.C., attys. of record, for appellants; George W.F. Simmons, Robert A. Doherty, Rohm Haas Co., Philadelphia, Pa., of counsel. Herbert B. Keil, Michael P. Bucklo, Johnston, Keil, Thompson Shurtleff, Chicago, Ill., David B. Kellom, Bernd W. Sandt, Midland, Mich., attys. of record, for appellees. Appeal from the Board of Patent Interferences. Before MARKEY, Chief Judge, and