Abstract: The effects of adding various stabilizers in the production steps, such as polymerization, quenching, extraction and oil treatment, on the insoluble sulfur (IS) content and stability of product were studied. Test results showed that the IS content and the stability of product could be improved by adding stabilizers in each step; the optimum selections were adding alcoholic stabilizer D in polymerization, water soluble organic stabilizer A in quenching and ester type liquid stabilizer X in extraction and oil treatment. Besides, based on the single stabilizer test results, optimization tests of two-stabilizer combination were carried out, yet no positive synergetic effect was observed.

Key words: insoluble sulfur, stabilizer, thermal stability