Behavior of Chlorine, Sulfur and Metals in Solid Residue during Thermal Decomposition of Chlorinated Synthetic Rubber

Shoji Ozawa*, Kenji Suyama**, Yasumasa Yamazaki**, Hitoki Matsuda* Toshikazu Kondo***, Satoshi Ota**** and Katsumasa Takeuchi***
* Research Center for Advanced Waste and Emission Management, Nagoya University
** Department of Energy and Engineering, Graduate of School Engineering, Nagoya University
*** Elastomer Material Engineering Dept., Material Eengineering Div., Toyoda Gosei Co., Ltd
****Material Engineering Div., Toyoda Gosei Co., Ltd
† Correspondence should be addressed to Hitoki Matsuda:
Research Center for Advanced Waste and Emission Management, Nagoya University
（Furo-cho, Chikusa-ku, Nagoya, 464-8603 Japan）


Abstract
For the recycling of waste rubber, the behavior of chlorine, sulfur and metals in solid residue during the thermal decomposition process of chlorinates synthetic rubbers with N2 atomosphere at a maximum temperature of 800℃ and a temperature rate of 5K/min was investigated. The experimental results obtained by employing chloroprene（CR）and nitrile butadiene rubbers mixed with polyvinyl chloride（NBR/PVC）are summarized as follows:
1）　More than 90wt％ of the chlorine contained in CR was converted to HCl gas, while about 60wt％ of sulfur remained in the solid residue. ZnCl2 was formed by the chlorination of ZnO involved in CR during the thermal decomposition of the CR, and migrated from the solid residue by volatilization. As a result, no zinc was observed in the solid residue of CR.
2）　Chlorine compounds generated from thermal decomposition of NBR/PVC were captured in the form of CaCl2 by CaCO3 filler, with a part of the CaCl2 remaining in the solid residue. Most of the sulfur was converted to sulfurous gases, while CaS was found as a remainder in the solid residue.


Key words: chloroprene rubbers, nitrile butadiene rubber, polyvinyl chloride, chlorine, sulfur