TBBPA — Tetrabromobisphenol A (Reactive Brominated FR for Epoxy)
Key Features
- Reactive FR — two OH groups bond covalently into epoxy laminate network
- Industry standard for FR-4 PCB laminates achieving UL 94 V-0
- 15–18% Br in cured laminate sufficient for V-0 fire performance
- Decades of manufacturing reliability data in high-volume PCB production
- SVHC under EU REACH — evaluate DOPO halogen-free alternative for new designs
Tetrabromobisphenol A (TBBPA, CAS 79-94-7) is the world's highest-volume reactive brominated flame retardant, used predominantly as a co-monomer in epoxy resin systems for printed circuit board (PCB) FR-4 laminates and as an additive FR in thermoplastic and thermoset systems. TBBPA's two hydroxyl groups react with epoxy resins during laminate formulation, chemically bonding bromine into the epoxy network. In FR-4 epoxy laminate formulations, TBBPA is used at 15–18% bromine content in the cured laminate, sufficient to achieve UL 94 V-0 rating and IPC-4101 fire performance.
TBBPA has been the dominant flame retardant in PCB laminates for decades due to its excellent compatibility with standard dicyandiamide (DICY) and phenolic novolac epoxy laminate chemistry, its demonstrated reliability in high-volume PCB manufacturing, and the vast database of product approvals under UL and IEC standards. Global production is approximately 150,000 tonnes/year, and it remains in widespread use for standard FR-4 and high-Tg FR-5 laminates.
Regulatory note: TBBPA is listed as a Substance of Very High Concern (SVHC) under EU REACH regulation due to its persistence and potential endocrine disruption. It is subject to authorization requirements for use in the EU in certain applications. While still widely used in PCB applications (which have authorization), new designs should evaluate halogen-free alternatives (DOPO, APP) for long-term regulatory compliance. TBBPA-based FR-4 laminates are still the cost-effective standard for most consumer electronics PCB production outside of specific restricted markets.
Specifications
| Parameter | Value |
|---|---|
| Purity | ≥ 98.0% |
| Appearance | White to off-white powder |
| CAS Number | 79-94-7 |
| Chemical name | Tetrabromobisphenol A |
| Melting point | 179–182°C |
| Bromine content | ~58.8% |
| Molecular weight | 543.9 g/mol |
| Hydroxyl equivalent weight | ~272 g/OH eq |
Applications
FAQ
TBBPA is not on the current RoHS Annex II restricted substance list (which restricts specific PBBs and PBDEs, not TBBPA specifically). However, TBBPA is listed as an SVHC under REACH, and its use in some applications in the EU requires authorization under REACH Article 60. For PCB laminates, TBBPA use is currently authorized. Always verify current regulatory status with your compliance team, as regulations change. For new product designs targeting long supply chain life or export to markets with stringent FR regulations, halogen-free (DOPO-based) laminates avoid regulatory uncertainty.
Direct Contact
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