A look at the benefits of flame retardants in circuits, their current regulatory and environmental status and their positive impact on the overall safety of ICT infrastructures
by Susan D. Landry, Albemarle
Tetrabromobisphenol-A (TBBPA) is the predominant flame retardant used in rigid FR-4 printed wiring boards (PWB). In this application, the TBBPA is fully reacted into the epoxy resins that form the base material of the PWB. TBBPA’s leadership position in the rigid printed wiring board market is due to several factors, which include reliable performance over time.
In a world where electronic equipment is frequently going through technological advances and changes, we are now experiencing a shift in chemical regulations and increase in market pressure. Many of the items we use on a daily basis, including electrical equipment, automobiles, and aircraft, are undergoing intense examination and scrutiny. The implications of the worldwide swing of regulatory programs impacts a broad range of materials, including flame retardants. The use of flame retardants has had a positive impact on the overall safety of homes, hotels, hospitals, nursing homes, offices, automobiles, and public transportation. Lives have been saved by the use of flame retardants. Flame retardants are used to delay the spread of fires or delay the time of flashover to enable people time to escape. While fire continues to be an ever-present threat to society, chemicals, including flame retardants, have been the object of considerable scrutiny. These concerns stem from the fact that low levels of particular materials can and have been detected in the environment and, in some cases, in animals and humans. Unfortunately, this can result in marketing pressure to eliminate specific chemicals or classes of chemicals, even without scientific justification or legislation to restrict these materials being in place.
Flame retardant regulatory activity
The pressure that chemicals have come under has lead to a patchwork of worldwide chemical regulations. Evaluation of the risks presented by the use of chemicals is the current focus of many regulatory programs. This approach takes into account the hazard of a substance, plus the exposure to the substance to determine the risk. The European Union (EU) Risk Assessment program (“Council Regulation [EEC] 793/93 of 23 March 1993”) is one process that was in place for over fifteen years and was used to evaluate the characteristics of a variety of high production volume chemicals. In July 1, 2007 the EU Risk Assessment process was replaced by the EU Registration, Evaluation and Authorization of Chemicals (REACH) Regulation. The principle of REACH is ‘no data, no market’. This approach is welcomed, as the importance to ensure that all flame retardants are safe for use, now and in the future is well recognized. In order to do this, regulatory decisions need to be based on sound science. These decisions also need to be made from a specific chemical’s risks, not simply hazards. The regulation system in place also needs to be adhered to and accepted by everyone. For our society to operate effectively and efficiently, then acceptance of good regulatory programs is of the utmost importance. No regulations exist that prohibit the use of TBBPA anywhere in the world. It is one of the most scientifically tested and most cost effective flame retardant available on the market.
EU RoHS directive
The Directive of the European Parliament and of the Council 2002/95/EC on the Restriction of the Use of certain Hazardous Substances in Electrical and Electronic Equipment (RoHS) was put into effect on July 1, 2006 and has recently been recast. It states that Member States shall ensure that new electrical and electronic equipment (EEE) put on the market shall not contain Pb, Hg, Cd, Cr (VI), polybrominated biphenyls (PBBs) and polybrominated diphenyl ethers (PBDEs) above de minimus levels. All other flame retardants are compliant with the provisions of the RoHS Directive and can hence be used in EEE. The RoHS recast went into effect on July 1, 2011. It promotes science-based legislation, underlines the importance of coherence of RoHS with other chemicals legislation (particularly the REACH Regulation), and includes a clear methodology for possible future restrictions of substances in electrical and electronic equipment. The recast RoHS will gradually open the scope of application to all electrical and electronic equipment over an 8-year period, from 2011 to 2019. TBBPA is not included or restricted under the current or recast RoHS Directive.
EU WEEE directive
The EU legislation promoting the collection and recycling of Waste of Electrical and Electronic Equipment (WEEE Directive) has been in force since February 2003. This directive calls for selective treatment of plastics containing brominated flame retardants. Also required within the directive is the separation of PWB of mobile phones (regardless of PWB size) and of other devices if the surface of the PWB is greater than 10 cm2, regardless of what flame retardant is contained. The reason is to recover the valuable extractable metals (Ag, Au, Cu, Zn, Al, Ni) from the PWB. The selective treatments of flame retardant plastics are fulfilled when the WEEE plastics are treated (recovered, recycled, thermally disposed) together with other wastes, as is the case with energy recovery processes that are currently practiced in Europe [16]. In this scenario, the joint recovery of plastics containing brominated flame retardants with other materials complies with the purpose of the WEEE Directive without the removal requirement of Annex II. Recent technical studies and legal reviews demonstrate that WEEE plastics containing brominated flame retardants, including TBBPA, are compatible with the EU WEEE Directive without separation and removal prior to the waste treatment. This has been confirmed by the 2006 EU Member States’ guidance on the separation requirements of the WEEE Directive. The EU WEEE Directive is currently undergoing Recast.
North American regulations
The Canadian federal government announced a new Chemical Substances Plan in December 2006 to prioritize chemicals targeted for risk assessment and risk management [17]. The first step of the Chemical Substances approach in Canada is categorization, followed by risk assessment and risk management. By 2006 some 23,000 chemical substances had been categorized to identify those that were:
- inherently toxic to humans or to the environment and that might be: o Persistent (take a very long time to break down), and/or o Bioaccumulative (collect in living organisms and end up in the food chain)
- substances to which people might have greatest potential for exposure. A screening risk assessment is underway in Canada for TBBPA.
The EPA’s Design for the Environment (DfE) Program focuses on the environmental, health, and safety aspects of flame retardants used in PWB [18]. It is a multi-stakeholder partnership with the goal to identify and evaluate commercially available flame retardants and their environmental and human health and safety aspects in FR-4 boards. The DfE project will try to determine the potential hazards associated with various flame retardants and potential exposures throughout the life cycle of flame retardants used in electronic FR-4 PWB. Consideration of exposures from manufacturing, use and incineration or burning at the end of life will be included. In addition, understanding the combustion products that could be formed during certain end of life scenarios will also be evaluated. The project began in February 2006. The Phase 1 report is complete and Phase 2 testing is in progress. The results show that once reacted with an epoxy to form the laminate, TBBPA had as good or better Human Health and Environmental properties than the alternatives.
Recycling and product stewardship
For PWB, the main end-of-life outlet is to smelters. Copper smelters, as well as precious metal smelters, are able to use PWB as a source for energy recovery (replacing cokes) and as a reducing agent for the metals. By smelting, the copper and precious metals can be recovered in the most economical and environmental safe manner. To produce copper from recycled material rather than from ore, means that only one-sixth of the energy is needed
Sustainability has become the goal for many companies and industries. The three aspects of sustainability (environmental, societal, and economic concerns) must be reconciled for sustainable development to be achieved. The chemical industry views sustainability as a challenge put before all parts of society. Advances made in industrial operations, improved performance, and improvements to society (by the use of flame retardants) all help to improve living standards and the environment. Reducing or eliminating emissions of chemicals to air and water can further minimize exposure to humans.
Printed wiring boards (PWB) are an integral part of the electrical and electronic equipment that has helped to improve our quality of life. TBBPA is a valuable flame retardant that has been used extensively in rigid FR-4 PWB for over 30 years to insure fire safety. It has had a long history of reliable use in this application. PWB containing TBBPA have an efficient and economical end-of-life option that is already in place.
Excellent product stewardship under the Voluntary Emissions Control Action Plan (VECAPTM) program will help to insure that TBBPA is kept out of the environment. By committing to applying pro-active product stewardship practices, the safe and environmentally friendly use of plastic additives, including TBBPA, can continue. VECAP encourages companies to critically analyze product flow and processes to identify the potential for emissions. It provides both a practical and cost-effective means of controlling emission, and is a potential model for chemical management that could be applied to all chemicals.