Overview#
Tetrabromobisphenol A is the most widely used brominated flame retardant, with the CAS number 79-94-7. Most of it is reacted into the epoxy resin of printed circuit board laminates, so it becomes part of the polymer rather than sitting loose. Smaller amounts are blended into some plastics as an additive. Because the reactive form is chemically bound, it behaves differently from additive flame retardants that can migrate.
Where it is controlled#
TBBPA is on the REACH REACH Candidate List after being identified as a substance of very high concern for its carcinogenic classification. Candidate List status brings declaration and notification duties through the supply chain. It is not banned, but it is flagged for attention.
Typical uses#
The dominant use is the reactive grade in circuit board laminates, where it bonds into the epoxy network and raises the board's resistance to ignition. The additive grade goes into some thermoplastics, where it is mixed in rather than reacted. This split matters because reactive use locks the molecule into the material.
TBBPA is one of the brominated flame retardants. It is the highest volume member of that family, driven by electronics demand.