Photoinitiator 819 (Bis-acylphosphine oxide, BAPO)
CAS Number: 162881-26-7
Photoinitiator 819 (BAPO) is a bis-acylphosphine oxide Type I photoinitiator with extremely broad absorption extending to 470 nm in the visible range. Each molecule yields two phosphinoyl radical pairs upon photolysis, providing twice the radical efficiency of monoacylphosphine initiators like TPO. It is the standard initiator for white, opaque, and highly pigmented UV systems including dental composites and LED-cured coatings.
Technical Specifications
| Purity | ≥98% (HPLC) |
| Appearance | Yellow to greenish-yellow crystalline powder |
| Melting Point | 127–133 °C |
| Molecular Weight | 496.5 g/mol |
| Absorption Maximum | 295 nm, 370 nm, 400 nm |
Applications
- White and opaque UV coatings and inks
- UV-LED curing at 385, 395, 405, and 450 nm
- Dental composites, adhesives, and orthodontic resins
- Thick-section UV potting and encapsulation
- UV-curable composites with high mineral filler loading
Key Features
- Photoinitiator 819 (BAPO) absorbs into the visible range at 470 nm for wide LED compatibility
- Bis-phosphinoyl structure generates two radical pairs per molecule — double efficiency vs. TPO
- Outstanding through-cure in white and opaque pigmented UV systems
- Standard initiator for dental composites with ISO 4049 photocure performance
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CAS Number
162881-26-7
Category
Radiation Curing ChemicalsAvailability
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