Environmental-Friendly and Non-Toxic TBSI as an Alternative for MOR Accelerator

Abstract

In the solid tyre rubber industry, most accelerators can produce n-nitrosamines as a by-product during the vulcanization process. As many n-nitrosamines are carcinogenic, they are highly regulated in final rubber articles and during manufacturing process.  2-(Morpholinothio benzothiazole (MOR) is the primary accelerator used in vulcanizing systems. It produces nitrogen toxic gases (nitrogen oxide and amine gas) which are carcinogenic. In this research MOR was successfully replaced with N-tert-butyl-2-benzothiazole sulfenimide (TBSI) accelerator which has no carcinogenic effect. The main objective of this research is to maintain its original properties while replacing MOR with TBSI accelerator.  This study was conducted and test samples were made of bonding rubber compound that is used to make the bonding layer of tyres which is the common part in all type of solid tyres. Physical-mechanical and bonding properties were analyzed for MOR and TBSI added bonding compound samples. Tensile, hardness, density and rheological using Oscillating die rheometer properties were also measured to maintain the quality of the tyre. The property change of bond layer can affects the other tyre layers. So, it can lead to failure of curing process or failure in performance of the tyre during the applications. The TBSI curing characteristics are closer to MOR sample. However other physical properties like hardness and density of TBSI samples were bit lower but they were in the required level as a bonding layer compound. Substitution of MOR by ‘safe TBSI’ compounds are still active as accelerators, but do not form carcinogenic gases.