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Carbon footprint of major flame retardants assessed

A research team led by Prof. Matthew Realff from the Georgia Institute of Technology has conducted a life cycle inventory study comparing two flame retardants used in Printed Circuit Board applications, TBBPA [1]and DOPO[2]. The focus of the study was to develop a methodology to estimate and compare the energy use and carbon footprint involved in the manufacture of these two flame retardants. The scope was from the extraction of the raw materials from the earth to the end of the flame retardant manufacturing process. The study was funded by the Bromine Science and Environmental Forum. An extension of the scope of the work was made to include the production of printed circuit board copper laminate layers.

The study used a methodology based on chemical engineering principles of mass and energy balances that establish process conditions based on industrially practiced processes. These unit operations and conditions were then reviewed by industrial process experts to ensure what represents current industrial practice.

The results show that:

o The overall carbon footprint of making DOPO is higher than that for TBBPA since more DOPO is
needed in the final product to ensure fire resistance.

The energy use in TBBPA and DOPO can be viewed as similar.

o The production of Phosphorus is very energy intense and generates a substantial amount of residue materials. The fraction of this energy that is allocated to DOPO is heavily influenced by the assumed fate of these residues (utilised as a product or disposed as a waste).

o The lowest energy-consuming route to TBBPA uses bromine from the Dead Sea. In addition, there are small differences within the manufacturing process of the TBBPA, depending on the solvents used.

o Significantly thicker printed circuit boards are needed using a DOPO like flame retardant as compared to a brominated one to achieve the same electronic and fire resistance performance. An increase in the mass of product increases the life cycle footprint.

A summary and presentation of the study by Prof. Realff at the conference Electronics Goes Green 2012 is available here.

For any additional information or enquiries, please contact:

Olalla Michelena – Consultant to BSEF- Burson Marsteller

+32 2 7436690 Olalla.michelena@bm.com

[1] Tetrabromobisphenyl A

[2] 9,10-Dihydro-9-oxa-10-phosphaphenanthrene 10-oxide