Resorcinol bis(diphenyl phosphate)

Resorcinol bis(diphenyl phosphate), commonly abbreviated as RDP or PFR and sold under trade names including CR 733S, LDP 301, and Mark PFK (CAS 57583-54-7, EC 260-830-6), is an organophosphate flame retardant with the molecular formula C30H24O8P2. It carries no assigned E-code and is classified under the Flame Retardants category.

RDP is used primarily in engineering thermoplastics such as PC/ABS and PPO/HIPS blends, where it achieves flame retardancy by releasing phosphoric acid species during combustion, promoting char formation and interrupting the combustion cycle. It simultaneously functions as a plasticizer, reducing melt viscosity and improving processability in electronics housings, automotive interior components, and aerospace cabin parts.

Supplied as a liquid grade under REACH registration, RDP is available in standard industrial packaging including drums and IBC containers. Procurement teams should confirm compliance documentation including Safety Data Sheets and REACH substance identity records prior to sourcing.