PATENTS - MONOPOLIES - CONTRIBUTORY INFRINGEMENT OF PROCESS PATENT

Plaintiff was the owner of a patent for the process of using bituminous emulsion to retard evaporation during the curing of concrete roads. Plaintiff supplied bituminous emulsion, an unpatented material, to road builders, permitting them to use the patented curing process, but had no express licenses or royalty contracts with these contractors. Defendant, a competing manufacturer of the emulsion, sold some of this material to a road builder, knowing that it was intended to be used in infringing the process patent. Plaintiff brought suit for contributory infringement against the supplier of the materials.

Held, that the owner of a process patent may not by suit for contributory infringement suppress competition in the sale of unpatented material used in conjunction with the process. Leitch Mfg. Co. v. Barber Co., 302 U. S. 458, 58 S. Ct. 288 (1938).