Polymer-containing ammonium polyphosphate

Figure 17.7 Char formation in polymer-containing ammonium polyphosphate as flame retardant.

Ammonium polyphosphates, on the other hand, are relatively water insoluble, nonmelting solids with very high phosphorus contents (up to about 30%). There are several crystalline forms and the commercial products differ in molecular weights, particle sizes, solubilities, and so on. They are also widely used as components of intumescent paints and mastics where they function as the acid catalyst (i.e., by producing phosphoric acid upon decomposition). They are used in paints with pentaerythritol (or with a derivative of pentaerythritol) as the carbonific component and melamine as the spumific compound.22 In addition, the intumescent formulations typically contain resinous binders, pigments, and other fillers. These systems are highly efficient in flame-retarding hydroxy-lated polymers. 

Phosphorus containing unsaturated polyesters Expandable graphite ammonium polyphosphate, triphenyl phosphate Flammability and thermal properties investigated, by UL 94 [13] and LOL Polymers containing ethylene glycol and ammonium polyphosphate showed the best flame retardance [44]... 

The product also works in non-halogenated systems. It can be used with ATH, MgO, ammonium polyphosphate, silica, silicone polymers or melamine compounds in polyolefins, urethanes, polyamides and others. In the silicon containing systems, Firebrake ZB is understood to form a borosilicate glass at polymer combustion temperatures. 

Clariant is the world s largest manufacturer of ammonium polyphosphate, which is the basis of its Exolit AP halogen-free intumescent flame retardants. They cut down smoke emission, evolve no corrosive gases and are recommended for both thermoplastic (including polyolefin and polyurethane) and thermosetting polymers. Exolit AP 750 is used to make injection moulded PP electrical parts and weatherable items that contain a HALS stabiliser. Ammonium polyphosphate is recommended for certain types of wood-plastic composite. 

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