Brominated flame retardant

Brominated flame retardants are a group of flame retardants that consist of organic compounds containing bromine.

Brominated flame retardants are the major type of chemical flame retardants, and are very effective in plastics and textile applications. They are applied to prevent electronics, clothes and furniture from catching fire.

Brominated flame retardants is the designated name for a group of brominated organic substances that have an inhibitory effect on the ignition of combustible organic materials. BFRs are commonly used in electronic products as a means of reducing the flammability of the product. Bromine based flame retardants are applied to 2.5 million tons of polymers annually, with the annual consumption of PBDEs alone being in excess of 40,000 metric tons. North American industry used about 34,000 metric tons of PBDEs in 1999, making it the largest user of these additives globally^[1]; however, a significant proportion of the flame-retarded products manufactured in North America is destined for international markets. The electronics industry accounts for the greatest consumption of BFRs. In computers, BFRs are used in four main applications: in printed circuit boards, in components such as connectors, in plastic covers, and in cables. BFRs are also used in a multitude of products, including, but not exclusively, plastic covers of television sets, carpets, paints, upholstery, and domestic kitchen appliances. BFRs have such a widespread number of applications because they are exceptionally effective at fire prevention. In addition to reducing the likelihood that an item will ignite, brominated flame retardants hinder the spread of the fire, and provide valuable extra time in the early stages of a fire when it is much easier to escape. A room fire can very quickly escalate to the point where enough heat is generated that all combustible material in the room bursts into flames. This situation is known as flashover and can occur in a matter of minutes from ignition. Brominated flame retardants slow down the initial burn rate and thereby can help increase the time to flashover, giving the occupants more time to escape.

Types of compounds

They are produced synthetically in 70 variants with very varying chemical properties. There are several groups:

• polybrominated diphenyl ether or PBDE (DecaBDE, OctaBDE (not manufactured anymore), PentaBDE(not manufactured anymore)),
• polybrominated biphenyl, or PBB(not manufactured anymore)
• brominated cyclohydrocarbons

Decabromodiphenyl ether (Deca-BDE or DeBDE) is regarded as a not-dangerous substance (no risk-phrase awarded under EU regulation 67/769).

Hexabromocyclododecane (HBCD or HBCDD) is a ring consisting of twelve carbon atoms with six bromine atoms tied to the ring. The commercially used HBCD is in fact a mixture of different isomers. HBCD is toxic to water-living organisms. Studies carried out on a HBCD product that is no longer manufactured indicate that Humans can develop allergy at skin contact.^{[citation needed]} This is not the case anymore with the current HBCD-based products.

Tetrabromobisphenol A (TBBPA or TBBP-A) is regarded as toxic to water environment.^{[citation needed]} This flame retardant is mainly used in printed circuit boards, as a reactive. Since TBBPA is chemically bound to the resin of the printed circuit board, it cannot be released and therefore poses no risk for the environment or for human health. TBBPA is also used as an additive in acrylonitrile butadiene styrene (ABS). EU risk assessment concluded in 2005 that TBBPA poses no risk to human health in that application.^{[citation needed]}

Contents in plastics

Content of brominated flame retardants in different polymers^[2]:

Testing for BFR in plastics

Until recently testing for BFR has been cumbersome. Cycle time, cost and level of expertise required for the test engineer has precluded the implementation of any screening of plastic component in a manufacturing or in a product qualification/validation environment.

Recently, with the introduction of a new analytical instrument IA-Mass, screening of plastic material alongside manufacturing line becomes possible. A 5 min. detection cycle and a 20 min. quantification cycle is available to test and to qualify plastic parts as they reach the assembly line. However, IA-Mass allow to identify the presence of Bromine (PBB, PBDE, and some others), but does not allow to characterize the all the BFR present in the plastic matrix.

In February 2009, the Institute for Reference Materials and Measurements (IRMM) released two certified reference materials (CRMs) to help analytical laboratories better detect two classes of flame retardants, namely polybrominated diphenyl ethers (PBDEs) and polybrominated biphenyls (PBBs). The two reference materials were custom made to contain all relevant PBDEs and PBBs at levels close to the legal limit set out in the RoHS Directive of 1 g/kg for the sum of PBBs and PBDEs.

Environmental and safety issues

This section requires expansion.

Many brominated chemicals are coming under increasing criticism in their use in household furnishings and where children would come into contact with them. Some believe the chemicals, including PBDE could have harmful effects on humans and animals. Increasing concern has prompted some European countries to ban some of them, following the precautionary principle more common in Europe.^{[3] [4]}

References

Further reading

• Birnbaum, Linda S. (2003). "Brominated Flame Retardants: Cause for Concern?". Environmental Health Perspectives. doi:10.1289/ehp.6559. 
• Kyle D'Silva, Alwyn Fernandes and Martin Rose (2004). "Brominated Organic Micropollutants—Igniting the Flame Retardant Issue". Critical Reviews in Environmental Science and Technology 34 (2): 141–207. doi:10.1080/10643380490430672. 
• Robin Law, Martin Kohler, Norbert Heeb, Andreas Gerecke, Peter Schmid, Stefan Voorspoels, Adrian Covaci, Georg Becher, Karel Janák, and Cathrine Thomsen (2005). "Hexabromocyclododecane challenges scientists and regulators". Critical Reviews in Environmental Science and Technology 34 (2): 281A–287A. PMID 16053062. http://pubs.acs.org/isubscribe/journals/esthag-a/39/i13/html/070105feature_law.html. 
• Cynthia A. de Wit (2002). "An overview of brominated flame retardants in the environment". Chemosphere 46 (5): 583–624. doi:10.1016/S0045-6535(01)00225-9. 

External links

• Jenny Nyholm 2009 Persistency, bioaccumulation and toxicity assessment of selected brominated flame retardants
• Sarah Janssen: Brominated Flame Retardants - Rising Levels of Concern, Health Care Without Harm, June 2005
• The Fire Retardant Forum Meeting place for all Flame Retardant related issues; for producers and users of flame retardants.
• Bromine Science and Environmental Forum
• European Brominated Flame Retardant Industry Panel
• SFT: Current State of Knowledge and Monitoring requirements: Emerging “new” Brominated flame retardants in flame retarded products and the environment