Ozone and wear resistance in styrene-butadiene rubber
AssigneeUniversity of Maryland, College Park
InventorJoseph Silverman
Life of this patent
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Abstract
SBR is treated with sulfur, an optional chemical accelerator and a crosslinking agent, under mild heat, to form a preform having sufficient strength to resist handling. The preform is exposed to substantial irradiation on the order of 5-25 Mrad dose of 10 MeV electrons equivalent, which significantly improves wear resistance, tear strength, crack initiation and growth resistance and ozone resistance.
Claims5
A method for improving physical and chemical characteristics of styrene-butadiend rubber comprising adding to a styrene-butadiene copolymer composition 0.1 phr-0.08 phr sulfur, 0-0.5 phr accelerator and 0.05 phr-2 phr 3,9-divinyl-2,4,8,10 tetraoxyspiro- undecane as a crosslinking agent, placing said mixture in a mold, and exposing the mold to moderate heat for sufficient time to form a preform having strength sufficient to retain the integrity of the molded form, and thereafter exposing said preform to an irradiation dosage of 5-25 Mrad of 10 MeV electron equivalent, wherein said sulfur, accelerator and crosslinking agent concentration, and irradiation dosage, are selected so as to provide tear resistance, in the product of that process, of 180-183 lbs/in, and an ozone resistance of at least 35 days, under standard ozone tests ASTM-D 1149, without evidence of ozone corrosion.
Dependencies are inferred from the claim text.