Ammonium Polyphosphate APP-Ⅱ 68333-79-9 BLT 433

BLIT Chemical is a professional manufacturer of Ammonium Polyphosphate (CAS 68333-79-9), a halogen-free, environmentally friendly flame retardant. Ammonium Polyphosphate (APP) is a white, non-hygroscopic powder known for its high thermal stability, low solubility, and strong char-forming ability. It is widely used in intumescent coatings, plastics, rubber, and textiles, offering excellent flame retardant performance. BLIT Chemical ensures consistent quality, full certification support, and competitive factory prices for global customers.

BLT 433 is a long-chain, high-polymerization crystalline Type II ammonium polyphosphate ((NH4PO3)n) product with a degree of polymerization (DP) ≥1000. Its high phosphorus and nitrogen contents create a synergistic P-N system, resulting in excellent flame retardancy and high thermal stability. It has low water solubility, a near-neutral pH, excellent dispersibility, good chemical stability, and good compatibility. It is a low-toxic, low-smoke, safe, and highly effective inorganic phosphorus-based flame retardant.

BLT 433 can be used in conjunction with charring agents and foaming agents for flame retardant treatment of thermoplastic materials such as PE/PP/PU, oxygen-containing materials, and high-end intumescent fire retardant coatings, demonstrating excellent flame retardancy.

Information

Synonyms	APP; Ammonium phosphate polymer; Polyphosphoric acid ammonium salt
CAS Number	68333-79-9
Chemical Formula	(NH4PO3)n
Molecular Weight	Variable (polymeric)
EINECS Number	269-789-9

Specification

Item	Unit	Index
Appearance	–	White Powder
Formula	–	(NH₄PO₃)ₙ
Degree of polymerization (n)	–	≥1000
P₂O₅ Content	%(w/w)	≥71
Nitrogen(N) Content	%(w/w)	≥14
pH Value (10% suspension)	–	5.5—8.5
Water Content (130℃)	%(w/w)	≤0.5
Solubility in water(25℃)	g/100mL	≤0.5
Viscosity (25℃, 10% suspension)	mPaS	≤100
Density (25℃)	g/cm³	about 1.9
Bulk Density (25℃)	g/cm³	about 0.7
Thermal Decomposition Temp. (5% weight loss)	℃	≥280
Crystal Form	–	Phase II
Average particle size (D50)	μm	≤20

Applications

APP-II, or ammonium polyphosphate, Phase II, is a green and environmentally friendly additive that achieves flame retardancy through the synergistic effect of phosphorus and nitrogen. Its core advantages include being halogen-free, low toxicity, highly thermally stable, and highly effective in flame retardancy. Its applications are highly focused on material systems requiring flame retardancy. The following are key applications for different materials.

The essence of APP-II is that it decomposes under heat to generate polyphosphoric acid (catalyzes carbonization) and ammonia (dilutes oxygen), and forms an insulating carbon layer through an expansion flame retardant mechanism. Therefore, it is mainly suitable for scenarios that require flame retardant modification, such as polymer materials, coatings, and textiles.

Material Application Field	Core Function	Simplified Application Logic	Key Advantages (Adaptability)
Plastics (PP, PE, etc.)	Core component of intumescent flame retardants	Direct blending and addition (10%-30% content); no complex modification required. It can directly upgrade the plastic’s flame-retardant rating to UL94 V-0.	Low migration, good compatibility with resins, and no significant negative impact on mechanical properties.
Fire-Retardant Coatings (steel structures/wood)	Forms an intumescent heat-insulating char layer to block flame spread	Compound into water-based/oil-based coating systems. Its small particle size (some products <5μm) ensures coating uniformity.	Low water solubility and high thermal stability (decomposition temperature >250℃).
Adhesives/Potting Compounds (for electronics)	Flame retardancy + adaptation to the “thin and transparent” requirements of electronic components	Used as a halogen-free flame-retardant additive, compatible with epoxy resin and polyurethane systems, meeting the “thinness and transparency” requirements of electronic adhesives.	Halogen-free & eco-friendly, minimal impact on bonding performance, and compliance with electronic industry standards.
Textiles/Foams (rigid polyurethane foam)	Flame-retardant coating for fabrics; fire-modification of foams	Coated on or blended into textile coatings/foam raw materials. Improves flame resistance while maintaining the flexibility of the base material.	Good dispersibility, no negative impact on the appearance and hand feel of the base material.

In addition to directly modifying materials, APP-II can also be used in wood flame retardant treatment processes, textile flame retardant finishing processes, and intumescent fire retardant coatings.

Storage & Handling

Store in a cool, dry, and well-ventilated warehouse away from moisture and acids. Avoid direct sunlight and high humidity. Keep containers tightly sealed when not in use.

Usage Guidelines

– Recommended dosage: 15–25 wt% depending on formulation.
– Compatible with melamine and pentaerythritol for intumescent systems.
– Processing temperature: below 300 °C.
– Ensure uniform dispersion for optimal flame retardant performance.

Packaging

Available in 25 kg woven bags with PE liners, 500 kg or 1000 kg jumbo bags, or customized packaging according to customer requirements.