Ammonium Polyphosphate (APP) Phase II
CAS Number: 68333-79-9
Featured inFlame Retardants
Ammonium polyphosphate Phase II (APP II) is a high-degree-of-polymerization, water-insoluble intumescent flame retardant widely used in coatings, adhesives, and polymer systems. With a polymerization degree exceeding 1000, it delivers superior humidity resistance and long-term durability compared to Phase I grades. APP II acts simultaneously as an acid source and blowing agent in intumescent systems, forming a protective char layer that suppresses flame spread.
Technical Specifications
| appearance | White powder |
| nitrogen content (%) | 14–15 |
| phosphorus content (%) | 31–32 |
| degree of polymerization | >1000 |
| decomposition temperature (°C) | >300 |
| water solubility (25°C, g/100mL) | <0.5 |
Applications
- Intumescent fireproofing coatings for steel structures
- Halogen-free flame retardant polypropylene and polyethylene compounds
- Expandable fire-retardant adhesives and sealants
- Wood and cellulosic substrate impregnation treatments
- Rigid polyurethane foam with improved fire resistance
Key Features
- High polymerization degree (>1000) ensures excellent water and humidity resistance
- Dual function as acid source and blowing agent in intumescent systems reduces additive count
- Halogen-free and low-smoke formulation meets REACH and RoHS compliance requirements
- Fine particle size (D50 ≈ 15 µm) promotes uniform dispersion in coatings and polymers
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CAS Number
68333-79-9
Category
Fire Retardant ChemicalsAvailability
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