Sulfur vulcanization are merely the additives used for vulcanisation and that other compounds may also be added to the rubber such as fillers or polymer stabilizers. Ordinary sulfur (octasulfur) is rarely used despite its low cost. Because of the low melting point of S vs the cure temperatures, attempted vulcanization with ordinary results in sulfur bloom. Instead, various forms of polymeric sulfur are used instead. It is also possible to replace sulfur with other sulfur-donating compounds, for example accelerators bearing disulphide groups, in what is often termed 'efficient vulcanization' (EV). Disulfur dichloride may also be used for 'cold vulcanization'. Under normal circumstances,
Union Sulphur Company original patents thus expired in 1908. Competitors such as the Freeport Sulphur Company quickly emerged and began to use the Frasch Process to extract sulfur from other nearby salt dome sites. The Union Sulphur Company tried to stop the Freeport Sulphur Company by suing on the basis of later patents that improved upon the original patents. The Delaware District Court largely sided with the Union Sulphur Co. The Third Circuit Court of Appeals, however, reversed the district court, concluding that the new patents were not really new inventions, but merely extensions of the original expired patents. Union Sulphur appealed to