Dr Xiudong Sun , vice president , research & applications , and Mike Goode , chief commercial officer , at FRX Polymers , look at an emerging alternative to flame retardants of concern
FLAME RETARDANTS
Polyphosphonate FRs fill the void
Dr Xiudong Sun , vice president , research & applications , and Mike Goode , chief commercial officer , at FRX Polymers , look at an emerging alternative to flame retardants of concern
The past two years have seen some of the most significant changes in flame retardant ( FR ) regulations ever . Actions have continued against individual chemicals such as TBPA , TCEP and melamine , which have become substances of very high concern ( SVHCs ) in the EU . More significantly , a legal finding in March 2022 confirmed actions to restrict the whole family of halogenated FRs in the enclosures and stands of TVs as valid .
This followed an essentially identical ban being signed into law in New York State on 31 December 2021 . Then in June 2023 , Washington State confirmed legislation that bans all halogenated FRs from the enclosures of essentially all electrical equipment in the home , and a requirement to notify the state of the presence of such FRs in outside equipment .
Additionally , the last 12 months have seen increasingly rapid action against per- and poly-fluoro chemical substances ( PFAS ). The common polycarbonate ( PC ) FR potassium perfluorobutanesulfonate ( KPFBS ), known as Rimar Salt , was issued with a Final Health Advisory in June 2022 and is already designated an SVHC in the EU . This was followed by Maine requiring notification of any intentionally added PFAS chemical in goods sold in the state from 1 January 2023 .
Typical Properties HM1100 HM7000 CO6000 CO6010-EX
Descriptions Homopolymer Homopolymer
In the meantime , there have been multi-billion dollar settlements between PFAS producers and different bodies affected by pollution , with 3M announcing its exit from fluorine products by the end of 2025 . OEMs and brand owners are moving more quickly and some are also requesting the removal of polytetrafluoroethylene ( PTFE ), which many NGOs and some regulatory authorities also consider to be a PFAS .
Polyphosphonate FRs
Driven by regulatory pressure and demand from OEMs and brand owners , many resin producers and compounders are looking for alternative FRs . In the last few months , FRX Polymers has received a steady flow of inquiries seeking FR solutions for PC and PC blends that are non-halogenated , KPFBS-free and PFAS free .
Copolymer , Copolymer , miscible with PC miscible with PC Phosphorus , % 10.60 % 10.60 % 6.60 % 6.60 %
Tg , ° C 105 104 121 121
MVR 260 ° C / 1.2 kg , cm 3 / 10min ”
20 40 8 8
YI 40 35 100 45
Figure 1 - Properties of Nofia polyphosphonate & poly ( phosphonate-co-carbonate ) grades
Nofia * is a family of halogen-free , phosphorus-containing , inherently FR polymers with outstanding safety profiles . Their polymeric nature means they are non-migrating and thus pose low concern to human health and the environment . They have received Green Screen ’ s Benchmark 3 accreditation , have been recognised by the ChemForward ‘ SAFER ’ programme , are TCOcertified and have been named to the Oeko-Tex 100 list .
The technology is based on a chemistry that allows the polymerisation of a phosphonate monomer into oligomeric and polymeric FRs . By using different co-monomers , the properties of the polyphosphonates can be tailored to specific needs . For example , by replacing some of the phosphonate monomer with diphenyl carbonate , various phosphorus-containing
SEP / OCT 2023 SPECCHEMONLINE . COM
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