Ammonium Polyphosphate (APP) is one of the most versatile and efficient flame retardant additives used across various industries, from plastics and coatings to textiles and construction materials. As environmental awareness and fire safety regulations continue to grow worldwide, APP has become a preferred choice for manufacturers seeking non-toxic, halogen-free, and thermally stable solutions. In this article, we will explore the properties, applications, performance characteristics, and importance of Ammonium Polyphosphate (APP), providing a clear technical overview suitable for professional reference.
Ammonium Polyphosphate (APP) is an inorganic salt composed of polymeric phosphate chains with ammonium ions. It acts as a highly effective flame retardant primarily through its ability to promote char formation and inhibit flame propagation.
When exposed to high temperatures, APP decomposes to release phosphoric acid and ammonia. The phosphoric acid helps create a stable carbonaceous char layer on the surface of the material, which effectively isolates the flame from the underlying substrate, reducing heat transfer and oxygen contact. This unique intumescent mechanism makes APP suitable for use in intumescent coatings, thermoplastics, rubbers, and textiles.
The increasing demand for environmentally friendly and halogen-free flame retardants has positioned APP as a preferred choice for engineers and manufacturers. Its outstanding chemical stability, low solubility in water, and high decomposition temperature make it ideal for applications that require durability under harsh conditions.
Furthermore, APP offers excellent compatibility with other intumescent ingredients, such as melamine and pentaerythritol, enhancing synergistic effects in flame retardant systems. This compatibility allows formulators to achieve superior fire performance without compromising mechanical strength or processability.
Below is a summary of the key technical specifications provided by Shandong Taixing Advanced Material Co., Ltd., a trusted supplier of Ammonium Polyphosphate (APP):
| Item | Specification | Test Method / Notes |
|---|---|---|
| Appearance | White Powder | Visual Inspection |
| Chemical Formula | (NH₄PO₃)n | Polymer Chain Structure |
| Phosphorus Content (as P) | ≥ 31% | Gravimetric Analysis |
| Nitrogen Content | ≥ 14% | Kjeldahl Method |
| Decomposition Temperature | ≥ 280°C | Thermal Gravimetric Analysis (TGA) |
| pH (10% aqueous suspension) | 5.5 – 7.5 | pH Meter |
| Solubility in Water (25°C) | ≤ 0.5 g/100mL | Measured at Room Temperature |
| Average Particle Size | ≤ 20 μm | Laser Diffraction |
| Moisture Content | ≤ 0.3% | IR Dryer |
| Phase Type | Type I or Type II | Determined by Thermal Stability and Chain Length |
Note:
Type I APP has shorter polymer chains and higher solubility, suitable for water-based coatings.
Type II APP features longer chains, excellent thermal stability, and lower solubility, ideal for plastics and intumescent coatings.
APP not only prevents flame spread but also enhances the overall performance of materials:
Superior Flame Retardancy – The formation of a dense, insulating char layer drastically reduces heat release and smoke generation.
Enhanced Durability – Due to its high decomposition temperature and low water solubility, APP maintains long-term stability in demanding environments.
Eco-Friendly Profile – It is halogen-free and non-toxic, producing minimal corrosive gases during combustion.
Wide Compatibility – Works effectively in epoxy resins, polyurethane foams, polypropylene, polyolefins, and coatings.
Cost Efficiency – Offers high flame retardant efficiency even at low loading rates.
APP's versatility allows its use across multiple industries:
Intumescent Coatings: Used in steel structure fireproof coatings for buildings, tunnels, and bridges.
Plastics and Polymers: Effective in polyolefins, epoxy resins, and engineering plastics for electrical and automotive applications.
Textiles and Fibers: Provides durable flame resistance in treated fabrics.
Rubber Compounds: Used in conveyor belts, seals, and protective coatings.
Wood and Paper Products: Improves flame resistance without altering surface properties.
Q1: What is the difference between Type I and Type II Ammonium Polyphosphate (APP)?
A1: Type I APP has a lower polymerization degree (n < 50), making it more soluble and suitable for water-based formulations. Type II APP has a higher polymerization degree (n > 1000), offering better thermal stability and lower solubility, preferred for thermoplastics and coatings.
Q2: How should Ammonium Polyphosphate (APP) be stored and handled?
A2: APP should be stored in a cool, dry place, away from moisture and direct sunlight. Containers must be tightly sealed to prevent water absorption. During handling, protective gloves and masks are recommended to avoid dust inhalation.
Q3: Is Ammonium Polyphosphate (APP) environmentally safe?
A3: Yes. APP is halogen-free, non-toxic, and does not release harmful gases when exposed to heat. It complies with major environmental standards, including RoHS and REACH, making it a sustainable choice for eco-conscious industries.
Q4: How can Ammonium Polyphosphate (APP) be incorporated into polymer systems?
A4: APP can be directly blended with polymer matrices or combined with synergistic agents like melamine and pentaerythritol to form intumescent flame retardant systems. Optimal loading typically ranges from 15–25% depending on the polymer type and desired fire resistance.
Shandong Taixing Advanced Material Co., Ltd. specializes in the research, production, and export of high-performance flame retardants, including Ammonium Polyphosphate (APP). With advanced manufacturing facilities and rigorous quality control systems, the company ensures stable product quality, competitive pricing, and reliable supply for global customers.
Key advantages include:
Consistent quality with batch-to-batch reliability
Customizable particle size and surface treatment
Strong R&D capability for formulation optimization
Global logistics support and timely delivery
Ammonium Polyphosphate (APP) is more than just a flame retardant—it is a multifunctional, eco-friendly solution driving safety innovation across industries. Its superior performance, thermal stability, and compatibility make it indispensable in modern material engineering.
For high-quality Ammonium Polyphosphate (APP) supply and technical support, please contact us at Shandong Taixing Advanced Material Co., Ltd.
