Opportunities for tin in flame retardants?
Antimony trioxide (ATO) has come under renewed pressure for its use in halogen based flame retardants, once again presenting an opportunity for future growth in tin usage in the sector, where zinc stannates are known as an effective substitute for the compound.
ICL innovation, technology incubator for major flame retardant producer ICL-IP, are currently offering to fund research for cost effective, sustainable and available alternatives to ATO for use in flame retardants, citing fluctuations in price and the need for continuing innovation in the area (See here).
Zinc stannates, developed by ITRI during the mid-1980's, have been primarily marketed as safe, low toxicity alternatives to ATO for use in PVC and other halogenated polymers. They can partially substitute for ATO in some formulations of fire retardant material, working best where minimal plasticizer is used. Total substitution is also possible in material such as rigid or semi-rigid PVC.
An estimated 130,000 tonnes of ATO was produced in 2013, according to the International Antimony Association. Of this, ITRI estimates 110,000 tonnes was used in flame retardants, compared to just 325 tonnes of tin in zinc stannates for the same purpose. Half substitution of ATO by zinc stannates with respect to this figure would be equivalent to some 25,000 tonnes of tin annually. Thus any signs that industrial manufacturers are under pressure to consider alternatives to ATO is significant.