Ammonium Polyphosphate
Exolit™ AP 435
Ausgabennummer :
3
Änderungsdatum :
September 02, 2026
Exolit AP 435 is a fine-particle phase II ammonium polyphosphate that contains less than 0.1% melamine. It is designed to provide low viscosity in aqueous suspensions and intumescent coating formulations. The product is largely insoluble in water and completely insoluble in organic solvents. It is colorless, non-hygroscopic, and non-flammable.
Product Information
Benefits
- Non-halogenated flame retardant with favorable environmental and health profile, free of SVHCs*)
- Optimized for low viscosity in aqueous suspension, low water solubility and low acid number.
- Particularly suitable as an ”acid donor” for intumescent coatings thanks to its low water solubility. Steel structures coated with intumescent coatings paints can meet the requirements of fire resistance classes specified in EN, DIN, BS, ASTM and others. Their application on wood or plastics enables these materials to qualify for Building Material Class B (DIN EN 13501-1).
- Imparts a good flame-retardant effect to adhesives and sealants when it is incorporated into the base formulation at the rate of 10 - 20%.
- Suitable non-halogenated flame retardant for polyurethane foams. PUR foams with Exolit AP 435 can be recycled.
- Excellent flame-retardant effect in cellulose containing materials such as paper and wood products. Chipboards containing 15 - 20 % Exolit AP 435 can achieve a class B-s1;d0 according to DIN EN 13501-1.
- Exolit AP 435 is an essential component in intumescent formulations for thermoplastics, particularly polypropylene, for which the classification UL 94-V0 is specified for applications in the electrical sector.
- In the case of thermosets like epoxy resins and unsaturated polyester resins, it paves the way for the production of lightweight components with low solid content.
- (Bio-)degradable by breaking down to naturally occurring phosphate and ammonia.
*) according to Article 31 of the REACH Regulation (Regulation (EC) No 1907/2006
Hazards
The product does not require a hazard warning label according CLP regulation (Regulation (EC) No. 1272/2008, as amended).
For further information please refer to the Material Safety Data Sheet.
| Characteristics | Unit | Target value | DS¹) | TD²) | Test method |
| Chemical Formula | [NH4PO3]n n > 1000 |
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| Phosphorus | % (w/w) | 31.0 - 32.0 |
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Photometry after oxidizing dissolution; (11/17) |
| Water / Moisture | % (w/w) | max. 0.25 |
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Thermogravimetry at 130 °C; (11/03) |
| Nitrogen | % (w/w) | 14.0 - 15.0 |
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Elemental analysis; (11/07) |
| Density | g/cm³ | 1.9 |
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at 25 °C |
| Bulk Density |
g/cm³ |
approx. 0.7 |
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| Viscosity | mPa*s | max. 40 |
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at 25 °C in 10 % aqueous suspension |
| pH Value | 5-8 |
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Potentiometry in 10 % aqueous suspension; (11/12) | |
| Solubility in Water | % (w/w) | max. 0.5 |
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Gravimetry after filtration of a 10 % aqueous suspension at 25 °C; (11/41) |
| Acid Number | mg KOH/g | max. 2 |
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Titration using alkali in 10 % aqueous suspension; (11/11) |
| Decomposition Temperature | °C | > 275 |
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Initial evolution of ammonia |
| Average Particle Size (D50) | µm | approx. 17 |
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| Particle Size Distribution | % (w/w) |
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Air jet sieving; (11/02) | |
| > 100 µm | max. 0.2 (DS) | ||||
| < 50 µm | min. 95 (TD) | ||||
| Weight Loss | % (w/w) |
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| 350 °C | approx. 5 | ||||
| 450 °C | approx. 10 | ||||
| 550 °C | approx. 20 | ||||
| ¹) Delivery specification: The product is monitored on a regular basis to ensure that it adheres to the specified values. Test methods: Clariant method numbers 11/xx in brackets. ²) Technical data: The technical data are used solely to describe the product and are not subject to regular monitoring. |
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Intumescent coatings
- On account of its low water solubility, Exolit AP 435 is particularly suitable as an ”acid donor” for intumescent coatings. Other essential components of intumescent systems include a binder, a carbon donor (e. g. pentaerythritol) and a blowing agent (e. g. melamine).
- On exposure to flame, intumescent coatings form a carbonaceous foam which effectively shields the underlying material from temperature increases.
- Steel structures coated with intumescent paints can meet the requirements of fire resistance classes specified in EN, DIN, BS, ASTM and others.
- The application of Exolit AP 435 based intumescent coatings on wood or plastics enables these materials to qualify for Building Material Class B (DIN EN 13501-1).
- Exolit AP 435 imparts a good flame-retardant effect to adhesives and sealants when it is incorporated into the base formulation at the rate of 10 - 20 %.
Polyurethane foams
- Exolit AP 435 is a suitable non-halogenated flame retardant for polyurethane foams. If handling of Exolit AP 435 as a solid is not possible we recommend the dosage of the flame retardant by preparing an Exolit AP 435 /polyol-suspension. Because of the low acid number of Exolit AP 435, it is also possible to incorporate this flame retardant in an Exolit AP 435/isocyanate suspension.
- To prevent the solids from settling, the Exolit AP 435 suspensions should be stirred or circulated by pump. The stirrers commonly found in service tanks are adequate for this purpose.
Other applications
- Exolit AP 435 has an excellent flame-retardant effect in cellulose containing materials such as paper and wood products. Chipboards containing 15 - 20 % Exolit AP 435 can achieve a class B-s1;d0 according to DIN EN 13501-1. Because of its high heat stability, Exolit AP 435 is an essential component in intumescent formulations for thermoplastics, particularly polypropylene, for which the classification UL 94-V0 is specified for applications in the electrical sector.
- Casting resins and composites based on epoxy resins or unsaturated polyester resins achieve the classification UL 94-V0 with Exolit AP 435. Combinations of Exolit AP 435 with ATH show synergistic effects in UL94 and LOI tests.
Delivery form
White powder
Packaging
Exolit AP 435 is packed in 25 kg 4-ply paper bags with polyethylene inliner. The standard supply unit is a shrink-wrapped pallet with 40 bags weighing 1.000 kg net. Exolit AP 435 can also be supplied in a variety of big bags, shrink-wrapped.
Storage
Minimum shelf life is 12 months from the date of shipping when stored according to the said conditions in the MSDS.
Documentation
Product Video
//www.youtube.com/embed/zpCoxNwLxOc
