Intumescent char
Forms an insulating foam char that protects the substrate.
APP
Ammonium Polyphosphate (APP) Supplier from China
Ammonium polyphosphate (APP) is a halogen-free phosphorus–nitrogen flame retardant used in intumescent coatings, polypropylene, epoxy, polyurethane, textiles and wood. SUNCHEM supplies APP with a batch COA on every shipment; the TDS is sent on request.
CAS 68333-79-9 · (NH₄PO₃)n · Phosphorus–nitrogen flame retardant
- Lot COA with every shipment
- Samples for your trials
- Technical support for your trial
Product overview & key benefits
APP releases phosphoric acid when heated, which chars the polymer, and ammonia, which blows the char into an insulating foam. With a carbon source such as pentaerythritol and a blowing agent such as melamine it forms the classic intumescent system used in fire-protective coatings for steel and wood, and in halogen-free polypropylene.
Long-chain crystal phase II APP has low water solubility and suits plastics and coatings; surface-treated grades further reduce water pick-up. Phosphorus, nitrogen, solubility and particle size are the numbers to compare.
Halogen-free, low smoke
No bromine or chlorine, with low smoke and corrosive gas.
Specified on your terms
We quote against your phosphorus and nitrogen content, crystal phase, degree of polymerization, water solubility, particle size and moisture and send the batch COA for each lot.
Technical specifications
| Parameter | Typical value |
|---|---|
| Product name | Ammonium Polyphosphate |
| Synonyms | APP; polyphosphoric acid, ammonium salt |
| CAS No. | 68333-79-9 |
| Formula | (NH₄PO₃)n |
| Appearance | White powder |
Phosphorus and nitrogen content, crystal phase, degree of polymerization, water solubility, particle size and moisture limits depend on the producer grade and are stated on the TDS and batch COA; the limits for your order are confirmed in the quotation and contract.
Applications by Polymer
Where APP is used, and what to confirm before you switch supply.
Intumescent fire-protective coatings
With pentaerythritol and melamine in fire-protective coatings for steel structures and wood.
Check before trial
- Coating type and fire standard
- Crystal phase and solubility
- Monthly volume
Halogen-free polypropylene
With a charring agent in halogen-free PP parts and in polyolefin compounds.
Check before trial
- UL 94 target
- Surface-treated or not
- Particle size
Epoxy, polyurethane, textiles and wood
Used in epoxy, rigid PU foam, textile back-coatings, wood and paper.
Check before trial
- Process
- Water resistance needs
- Sample for trials
Selection & comparison
Choosing the right APP grade
| Your requirement | What usually works |
|---|---|
| Intumescent coatings | Crystal phase II APP with low solubility |
| Halogen-free PP | Phase II or surface-treated APP with a charring agent |
| Humid service conditions | Surface-treated (coated) grade |
| Replacing an existing supplier | Send your current TDS or COA; we quote against the parameters you approve |
Packaging & storage
Packaging
Tell us the bag or drum size and pallet requirements you need; we confirm the packaging with the quotation.
Storage
Keep bags closed in a dry store; APP absorbs moisture.
From first email to approved supply
Name the end use
Name the polymer and the fire rating you must meet — UL 94 class and thickness, LOI or cable standard.
Compare the numbers that matter
Phosphorus and nitrogen, crystal phase, degree of polymerization, water solubility, particle size and moisture.
Design the full system
APP works with a carbon source and blowing agent; test the complete formula, not APP alone.
Trial, then lock the spec
Compound a trial batch, run your fire and mechanical tests, and keep the approved lot COA as the reference.
Tell us your requirement. We match the grade.
Tell us the polymer, the fire rating you need, the quantity and the destination port. Add your current specification and we will quote against it.
| Information | Example |
|---|---|
| Application | Coatings, PP, epoxy, PU, textiles, wood |
| Required specification | Crystal phase, solubility, particle size |
| Packaging | Bag or drum size; pallets |
| Quantity | Sample / trial order / annual volume |
| Destination | Country and port |
| Documents needed | COA, SDS, TDS, RoHS/REACH |
Related products
Aluminum Hydroxide
Mineral flame retardant and smoke suppressant for cables and resins.
View product →Ammonium Polyphosphate (APP) FAQ
What is APP used for?
In intumescent fire-protective coatings, halogen-free PP, epoxy, PU foam, textiles, wood and paper.
What is phase II APP?
A long-chain crystal form with low water solubility, preferred for plastics and coatings.
Which parameters should I compare between offers?
Phosphorus and nitrogen content, crystal phase, solubility, particle size and moisture.
Can I get the TDS?
Yes. Send an inquiry with your application and we email the TDS.
