Abstract: This article reported the effects of epoxidized soybean oil, Phosphite, βdiketone and hydrotalcite as auxiliary heat stabilizers as well as a Ca/Zn-type primary heat stabilizer on thermal stability, mechanical properties and smoke density of soft poly(vinyl chloride) (PVC) compounds. The investigating results indicated that the soft PVC achieved a long-term thermal stability and low smoke density by compounding hydrotalcite with Ca/Zn-type heat stabilizer in comparison with other auxiliary heat stabilizers.

Key words: hydrotalcite, poly（vinyl chloride）, thermal stability, auxiliary heat stabilizer