Flame Retardants
REACH
tert-Butylphenyl diphenyl phosphate
CAS Number
56803-37-3
EC Number
260-391-0
What is tert-Butylphenyl diphenyl phosphate?
tert-Butylphenyl diphenyl phosphate (CAS 56803-37-3), also known commercially as butylated triphenyl phosphate, is an organophosphate ester used as both a flame retardant and plasticizer in polymer systems.
Where is tert-Butylphenyl diphenyl phosphate used?
- Electronics: printed circuit board laminates and connector housings
- Encapsulant resins requiring UL 94 flame ratings with dimensional stability
- Automotive interior components: instrument panels and wire harness insulation
- Under-hood polymer parts meeting fire resistance standards
- Aerospace and defense: high-performance polymer composites and coatings
- It improves melt flow as a secondary plasticizer in rigid PVC and engineering thermoplastics.
Good to know: In electronics, automotive, aerospace and defense sectors, halogen-free flame retardancy is a qualification requirement.
Commercial specifications
- Purity specifications typically 97% or above
- Bulk liquid quantities and intermediate packaging such as drums and IBCs
Other Names (Synonyms)
Phosphoric acid, (1,1-dimethylethyl)phenyl diphenyl ester|Butylated triphenyl phosphate|(2-tert-butylphenyl) diphenyl phosphate
What are the physical properties of tert-Butylphenyl diphenyl phosphate?
Boiling Point 261 °C @ Press: 6 Torr
Density 1.180 g/cm³ @ Temp: 25 °C
Flash Point 224°C
Color White to Pale Yellow
Form Low-Melting Solid
Water Solubility <0.1 g/100 mL at 21 ºC
Refractive Index 1.555
How is tert-Butylphenyl diphenyl phosphate classified and handled safely? Learn More
Warning
GHS08· Health Hazard
Hazard Statements
H373 May causes damage to organs through prolonged or repeated exposure [Warning Specific target organ toxicity, repeated exposure]