Abstract
N-(R-thio)-N-cyclohexylbenzothiazyl-2-sulfonamides [I] were effective to inhibit prevulcanization in sulfur vulcanization.
Above all, [I] (R=iso-C3H7, sec-C4H9, C6H11) were very effective as a scorch retarder.
It was proved that a small amount of iso-PCBS (I, R=iso-C3H7) inhibits scorching in various accelerator systems. Iso-PCBS was particularly effective in controlling scorch delay with all kinds of sulfenamide accelerators without giving significant influences on cure rate or physical properties of the vulcanizates. Scorch time was longer proportionaly to the amount of iso-PCBS.
Iso-PCBS reacts with 2-mercaptobenzothiazole, forming iso-propyldithiobenzothiazole and N-cyclohexylbenzothiazyl-2-sulfonamide (CBSA).
Iso-PCBS reacts with morpholine, forming iso-propylthiomorpholine and CBSA.
