The U.S. EPA published in June 2014 their final report on “Flame Retardant Alternatives for Hexabromocyclododecane (HBCD). Note: Hexabromocyclododecane is sometimes also abbreviated as HBCDD. The project was executed under the U.S. EPA’s Design for Environment (DfE) program, being launched in 2011 and having been completed this year. The DfE program concluded that the dominant use of HBCD is in expanded and extruded polystyrene foam (EPS and XPS) insulation under current manufacturing processes. HBCD is also used as a flame retardant for High impact polystyrene (HIPS) often in electronic audio\/video products. This application accounts for a small percentage of the total HBCD used, but it is still a significant impact for electronic products using this substance. <\/p>\n
HBCD is being phased out because of its high concerns in the area of human development, very high aquatic toxicity, high persistence and very high bioaccumulation in the environment. Many countries are in the process of implementing restrictions on the use of HBCD and it is likely to become one of the restricted substances under the RoHS Directive. HBCD is already on the REACH Annex XIV authorization list and therefore also listed as a REACH Candidate List SVHC. <\/p>\n
Given the dominant use of HBCD in the building and construction industry, the DfE project focused on these applications. Therefore the results of the study itself are not particularly useful for the electrical and electronics (EEE) industry. Instead, the final report refers EEE manufacturers to the results from the earlier DfE study on “An Alternatives Assessment For The Flame Retardant Decabromodiphenyl Ether (DecaBDE)” — we provide more information on this topic later in the blog posting. <\/p>\n
For HBCD in EPS and XPS, the report identifies three alternatives that tend to have lower human health and environment endpoint concerns than HBCD: a butadiene styrene brominated copolymer (CAS 1195978-93-8), a TBBPA-bis brominated ether derivative (CAS 97416-84-7), and TBBPA bis(2,3-dibromopropyl) ether (CAS 21850-44-2). Of these three alternatives, butadiene styrene brominated copolymer (CAS 1195978-93-8) appears to have the lowest human health and environmental impacts; however, the overall impact will also be influenced by the end application. <\/p>\n
For the electronics industry, the U.S. EPA points manufacturers to the DfE study on alternatives to Decabromodiphenyl Ether (DecaBDE) because decBDE was commonly used as a flame retardent for HIPS prior to the decaBDE ban in the EU RoHS Directive. Therefore, the alternatives for replacing decaBDE in HIPS may also be applicable to replacing HBCD in HIPS (depending on the specific performance aspects that are required by your application). The alternatives that were considered for HIPS include: Antimony trioxide (as a synergist only); Bis (hexachlorocyclopentadieno) cyclooctane; Brominated Epoxy Polymer(s); Mixture of Brominated Epoxy Polymer(s) and Bromobenzyl Acrylate; Brominated epoxy resin end-capped with tribromophenol; Brominated poly(phenylether); Decabromodiphenyl ethane; Ethylene bis-tetrabromophthalimide; and Tris(tribromophenoxy) triazine. <\/p>\n
The DfE report does not specifically recommend any of the alternatives given that each alternative has its own pros and cons. However, the report provides information about a variety of human toxicity and environmental impact endpoints for each alternative to help manufacturers identify and assess potential alternatives for use in their materials. The potential real impact of any of these chemicals also depends on the application and the use of the final product itself. Some of the alternatives have some significant human toxicity or environmental impacts and may not be any better than HBCD. The DfE report for decaBDE is available from the project website<\/a>. <\/p>\n The DfE alternatives assessment report is available from the project website<\/a>. <\/p>\n