Ammonium Polyphosphate (Food Grade)

Brief Overview 

Ammonium Polyphosphate (APP) is a 100% water-soluble phosphate that is mostly used in plants. APP is an inorganic salt of ammonia and polyphosphoric acid, whose chain length is variable and branched. Short-length APP chains are water sensitive and unstable compared to longer-chain APP. There are two main families of APP Crystal Phase 1 APP (linear structure) and Crystal Phase 11 APP (branched structure). APP is a non-toxic, environmentally friendly material, and it is used as flame retardant as it does not generate smoke due to the unique mechanism of intumescence

Manufacturing Process

APP is prepared by a reaction between concentrated phosphoric acid with ammonia. However, impurities consisting of iron and aluminum are soluble in concentrated phosphoric acid, which forms gelatinous precipitates in APP.  In industrials, APP is manufactured by polycondensation between mono ammonium phosphate and urea.

Food Industry 

In the food industry, it is primarily used as a food additive and a source of phosphorus. 

Fertilizer Industry 

APP is used as a fertilizer for many crops as it is a rich source of phosphorus and nitrogen. The ratio of N₂:P₂O₅ is suitable for many crops, and this combination improves the plant nutrient intake and lets the plant utilize phosphorus more efficiently. APP contains polyphosphates which extract micronutrients in solution, aiding in the uptake of micronutrients and making them easily available for the plant.

Flame Retardants

APP is a very efficient halogen-free flame retardant mainly used in polyolefin (PE, PP), thermoset resins such as epoxy resins, and polyurethane, unsaturated polyester phenolic resins. It is an intumescent flame-retardant component for coating, wood, paper, plywood, cable, fiber, plastic, rubber, and resin. It is a component of fire-extinguishing dry powder for fire in a forest, oil well, and coal mine.

Other Applications

APP is also used as a nutrient for yeast and increases its water-binding properties. It is mainly used in processed cheese and frozen poultry.