ZnS - Substitution of Sb2O3

Remarks： ①Use 10% + brominated diphenyl ethers as flame retardants；

②This item UL-94 is not listed

The table above lists the oxygen index value requirements corresponding to different plastic types when ZnS or Sb₂O₃ alone or an equivalent ratio mixture of the two is used as flame retardant. According to the UL-94 test method, the flammability grades of the materials are listed together. When Sb₂O₃ is replaced by 50% of ZnS, most of its applications in other plastics, except PA-6, are at the same flame retardant level of UL-94. In PA-6, the flame retardant data was poor when 50% of ZnS was used to replace Sb₂O_3, which was V2. However, the effect was good when all of ZnS was used as flame retardant additive.

For PVC, PP and PS, better oxygen index values were tested when 50% of ZnS was added instead of Sb₂O_3. According to the oxygen index value and UL-94 two test methods, the possibility of replacing Sb₂O₃ with ZnS is summarized as follows: PVC-U can replace 100%; PVC-P can replace 75%; PVC paste can replace 50%; HDPE can replace 50%; PP can replace 50%; PS can replace 100%; PA-6 is not suitable for partial replacement, but can replace all; PET can replace 50%; ABS is not suitable for replacement.

From the analysis of the combined effect of whitening and flame retardant, the test results show that some or all of Sb₂O₃ can be replaced by ZnS. ZnS as a white pigment shows a bright hue, which is about 60% of the whitening ability of titanium dioxide. As a flame retardant, ZnS can save the amount of TiO₂ added. Moreover, ZnS is non-toxic, so for PVC processing, it can be used as a corresponding flame retardant additive that meets the requirements of environmental regulations.