Skip to main content
  • Clariant Logo
  • Share
  • Contact
  • en - US
  • Translate
  • Contrast
  • Search
  • Products & Industries
  • Sustainability
  • Company
  • Media
  • Investors
  • Careers
  • Events
Close
Search
Close
SDS & Document Finder
result(s)
All Results
Close
Facebook Twitter LinkedIn E-Mail WhatsApp More Options
Close
Close
The translation will be performed automatically using AI. Please double-check important facts and statements.
Close
Clariant International
  • Products & Industries
  • Sustainability
  • Company
  • Media
  • Investors
  • Careers
  • Events
Home / Products & Industries / Products / Exolit™ AP 423
Products
Summarize
Micronized APP (phase II) with extremely low water solubility

Exolit™ AP 423

Edition Date :
February 06, 2026

Exolit AP 423 is a very fine-particle ammonium polyphosphate produced by a special method. The crystal modification is phase II. The product is largely insoluble in water and completely insoluble in organic solvents. It is a white powder, halogen free and non-flammable. 

Order sample Product Data Sheet

Product Information

Benefits
  • Low solubility in water, low viscosity in aqueous suspensions and a low acid number
  • Imparts a good flame-retardant effect to adhesives and sealants when incorporated into the base formulation at the rate of 10 - 20%
  • Particularly suitable as an ”acid donor” for intumescent coatings thanks to its low water solubility. 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 423 based intumescent coatings on wood or plastics enables these materials to qualify for Building Material Class B (DIN EN 13501-1)
  • Can be used in transport applications to obtain good fire, smoke and toxicity results (EN 45545)
  • (Bio-)degradable by breaking down to naturally occurring phosphate and ammonia
  • Non-halogenated flame retardant with favorable environmental and health profile

 

For regulatory details such as the classification and labelling as dangerous substances or goods please refer to our corresponding Material Safety Data Sheet.
Characteristics  Unit   Target value   DS¹)    TD²)  Test method 
Chemical Formula  [NH4PO3]n
n > 1000  

☐

☑

Phosphorus  %(w/w)   31.0 - 32.0  

☑

☐

Photometry after oxidizing dissolution; (11/17)  
Water / Moisture  %(w/w)   max. 0.5  

☑

☐

Thermogravimetry at 130 °C; (11/03)  
Nitrogen  %(w/w)   14.0 - 15.0  

☑

☐

Elemental analysis; (11/07)  
Density  g/cm³   1.9  

☐

☑

at 25 °C  
Bulk Density  g/cm³   approx. 0.7  

☐

☑

Viscosity  mPa*s   max. 100  

☐

☑

at 25 °C in 10 % aqueous suspension  
pH Value  5.0 - 7.5  

☑

☐

Potentiometry in 10 % aqueous suspension; (11/12)  
Solubility in Water  %(w/w)   max. 1.0  

☑

☐

Gravimetry after filtration of a 10 % aqueous suspension at 25°C; (11/41)  
Decomposition Temperature  °C   > 275  

☐

☑

initial evolution of ammonia  
Average Particle Size (D50)  µm   approx. 8  

☐

☑

 
Particle Size Distribution  %(w/w)  

☑

☐

Air jet sieving; (11/02)  
< 24 µm   min. 97 (TD)    
> 50 µm   max. 0.1 (DS)    
-  
-    
-    
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.  
Intumescent coatings
On account of its low water solubility, Exolit AP 423 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 DIN, BS or ASTM.    

The application of Exolit AP 423 based intumescent coatings on wood or plastics enables these materials to qualify for Building Material Class B (DIN EN 13501-1).

Exolit AP 423 imparts a good flame-retardant effect to adhesives and sealants when it is incorporated into the base formulation at the rate of 10 - 20 %.

 

Other applications
In composites for transport applications it can be used to control fire, smoke and toxicity. Especially in railway (EN 45545-2) and aviation (FAR 25.853) applications low smoke density and toxicity is a key requirement.

Due to the fine particles it can be used for infusion processing technics.

Delivery form
White powder

Packaging
Exolit AP 423 is packed in 25 kg bags. The standard supply unit is a shrink-wrapped pallet with 40 bags weig­hing 1000 kg net.

Storage
Minimum shelf life is 6 months from the date of shipping when stored according to the said conditions.

Documentation

Download File

Close

Login Required

close
Log in or register to ClariHub for our full set of product documentation and more resources.
Create Account
Login

Authorization required

close
You do not have the required permissions to access the protected files related to this product. If you would like to get access, please do not hesitate to contact us.
Clariant International
          Clariant International
          We at Clariant are aware of our responsibility. Our purpose »Greater chemistry – between people and planet« describes the role we can play in the world if we align our thinking and all future decisions with it.
          Social
          • Imprint
          • Terms of Use
          • Data protection and privacy
          • General Terms and Conditions of Sale and Purchase
          Copyright © Clariant 2026. All rights reserved.

          Page summary

          close
          Summarization in progress
          The page summary is generated by AI