Are there substitutes for Antimony Trioxide (AO) in PVC and other halogen-containing plastics?
The uniqueness of AO is its ability to react to form powerful volatile flame inhibitory antimony trichloride or tribromide. So, if the formulation contains considerable flammable volatile material like typical PVC plasticizers, it is hard to totally dispense with AO. Zinc stannates and zinc borates can partially substitute for AO in some formulations. The substitution is best in systems with little or no plasticizer. There are even some cases where total substitution can be done, such as in rigid or semi-rigid PVC. There may be some less volatile plasticizers that would make it easier to replace AO.
Can we drastically lower or eliminate the loading of ATO?
Customers have found that Marshall Additive Technologies’ C-TEC FRZ series can do that. These products are inorganic compositions with reduced % of AO, plus inorganic ingredients acting as carriers and activity boosters to substantially enhance the AO content, and as a “bonus” reduce smoke. Even when the price of AO was much lower, there were customers for the C-TEC FRZ series who enjoyed the price/performance advantage. The advantage has become increasingly greater.
Recommendation:
Evaluate C-TEC FRZ20S in your PVC formulation by replacing AO at the same level. If favorable results are obtained, try FD415. If results fall short, try FD373 to meet your objective.