additives feature | Fire retardants He adds that the combination of high bromine costs,
regulations, and environmental concerns have been a trigger for FR suppliers to develop new flame retardant chemicals. These are designed to provide compound- ers, such as RTP, with new tools to develop innovative and unique FR formulations to meet industry needs. Shen adds that in addition to the emergence of new
and improved halogen-free compounds – particularly, nitrogen, phosphorous and silicon type compounds – he sees new endeavours focused on developing FR packages composed of more than one or two such additives. He, and other industry sources, note that within the past two years, there has been more opportu- nity for halogen-free flame retardants to broaden their reach. This has been driven not only by environmental pressures, but also escalating prices of both brominated flame retardants and antimony oxide, which is widely used as a synergist in halogenated formulations. Rio Tinto’s Firebrake ZB zinc borate has benefited
from rising antimony oxide prices, offering a lower cost replacement in halogenated FR systems, according to Shen. In addition, it provides enhanced colour and thermal stability, he claims. Firebrake ZB can be used as a multifunctional, cost-effective flame retardant and smoke suppressant in both halogen and halogen-free plastics. It displays synergistic effects with brominated systems, metal hydroxides, nitrogen/phosphorous compounds, and silicon-based flame retardants. MPI Chemie, a supplier of both halogen-free and
Ampacet produces FR
masterbatches for polyolefins, targeting
applications such as wire and cable
brominated flame retardants has focused on polyole- fins, PBT and PA 6 and 66, and in more recent years also on PC/ABS blends, PET sheet and epoxy resin. The company’s CEO Ele de Haas notes that the impact of the global economy means that all sectors of the thermo- plastics industry are focusing on improving cost- efficiencies. “Compounders, for instance, are now not only focusing on halogen- free alternatives, but are also looking at alternative suppliers for existing brominated flame retardants,” he says. Joseph Serbaroli is
strategic business manager for infrastructure applica- tions at Ampacet, a major producer of FR additive masterbatches for polyolefins, targeting applications such as wire and cable, specialty films and injection- moulded components for transportation. He says that new flame-retardant chemistries face a tough challenge to improve on existing products. “In terms of polyolefin masterbatches, we have not seen anything better than existing brominated flame retardants, particularly in terms of cost/performance. Many of the alternatives typically prove to be either too difficult to handle or difficult to process and this is one of the barriers of entry for alternative chemistries.” Serbaroli adds that Ampacet is very fixated on worker safety and that any FR chemicals that would pose a health hazard to its workers are screened-out ahead of time.
Replacing decaBDE Some of the most intense FR development work is focused on finding replacements for decabromodiphe- nyl ether (decaBDE), which is being phased out by the three global leaders in brominated flame retardants, Albemarle, Chemtura/Great Lakes and ICL Industries. This phase-out process commenced in 2009 and will be complete by 2013. It is a major undertaking as decaBDE has been widely used as a workhorse, general-purpose FR additive for nearly 40 years in polyolefin wire and cable applications and in HIPS and PBT materials for the electrical and electronic sectors. Among the first decaBDE alternatives to emerge,
even before the ‘voluntary phase-out, was aromatic bromine ethane, 1,2-Bis(pentabromophenyl), also known as decabromo diphenylethane. It first was commercial- ized by Albemarle as Saytex 8010 about four years ago, quickly followed by Chemtura’s Great Lakes Solutions FR business with its version, Firemaster 2100R. This molecule has been demonstrated to be both
more thermally stable and largely non-blooming. Still, there are a couple of issues: the first is that there is not enough availability to replace decaBDE; and, while there are no existing toxicity
restrictions on ethane, there have been some risk assessment studies conducted in Canada which make some users feel that other replacements could provide them with more
confidence. within the past two years, new polymeric flame
retardants with high bromine contents have been developed by the ‘big three’. They are marketed as drop-in replacements for decaBDE in a range of polymers including styrenics, polyolefins, polyester, nylon and TPEs. They are touted for their improved sustainability and very good environmental profiles in
34 COMPOunDInG wORLD | December 2011
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