United States Patent Office Patented Feb
3,563,962 United States Patent Office Patented Feb. 16, 1971 1. 2 3,563,962 Such as benzene, heptane, carbon tetrachloride, toluene RUBBER WULCANIZATION AGENTS AND and the like. METHODS FOR THEIR PREPARATION The most useful diolefins are those which are cyclic Stanley B. Mirviss, Stamford, Conn., assignor to Stauffer conjugated compounds, such as cyclopentadiene, dimethyl Chemical Company, New York, N.Y., a corporation of cyclopentadiene, cyclohexadiene-1,3, cyclooctadiene-1,3 Delaware and 1-vinylcyclohexene. For some reason the process of No Drawing. Filed Dec. 13, 1967, Ser. No. 690,062 this invention provides no adavntageous changes in prop int, C. C08f 27/06 erties when applied to isoprenes and similar linear diole U.S. C. 260-79 7 Claims fins. As will be apparent to those skilled in the art, other 10 cyclic olefins can also be selected which, while not them Selves conjugated, will crack to form a conjugated diole ABSTRACT OF THE DISCLOSURE fin under the particular heating conditions employed. For Superior vulcanization agents for rubber are prepared instance, one of the preferred reactants of this invention by heating conjugated diolefins with sulfur in the presence is the dimer of cyclopentadiene, i.e. dicyclopentadiene, of catalytic amounts of phosphorus sulfides. 5 which on heating above about 100° C. cracks to form cyclopentadiene which then reacts with the sulfur. The phosphorus sulfide may be chosen from any of the BACKGROUND OF THE INVENTION well-known compounds of this class, for instance PS, PS3, PASS, PS, P4S10 (P2S5) and PAOS4. Particularly This invention relates to novel vulcanization agents preferred by reason of their relative availability, cost and for rubber and methods for their preparation, and also to efficiency are phosphorus sesquisulfide (PS) and phos the resulting vulcanizates which comprise a major pro phorus pentasulfide (P2S5).
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