AMMONIUM POLYPHOSPHATE

Ammonium Polyphosphate is an environment-friendly, non-toxic, halogen-free flame retardant, chemically Ammonium Polyphosphate is an organic salt of polyphosphoric acid and ammonia. Ammonium polyphosphate commercially produced by Clariant, (former business area of Hoechst AG), Budenheim and other sources is an inorganic salt of polyphosphoric acid and ammonia containing both chains and possibly branching. Its chemical formula is [NH4 PO3]n(OH)2 showing that each monomer consists of an orthophosphate radical of a phosphorus atom with three oxygens and one negative charge neutralized by an ammonium cation leaving two bonds free to polymerize. In the branched cases some monomers are missing the ammonium anion and instead link to three other monomers. 
The properties of ammonium polyphosphate depend on the number of monomers in each molecule and to a degree on how often it branches. Shorter chains (n<100) are more water sensitive and less thermally stable than longer chains (n>1000), but short polymer chains (e.g. pyro-, tripoly-, and tetrapoly-) are more soluble and show increasing solubility with increasing chain length. 
Ammonium polyphosphate can be prepared by reacting concentrated phosphoric acid with ammonia. However, iron and aluminum impurities, soluble in concentrated phosphoric acid, form gelatinous precipitates or "sludges" in ammonium polyphosphate at pH between 5 and 7. Other metal impurities such as copper, chromium, magnesium, and zinc form granular precipitates. However, depending on the degree of polymerization, ammonium polyphosphate can act as a chelating agent to keep certain metal ions dissolved in solution. Ammonium polyphosphate is used as a food additive, emulsifier, (E number: E545) and as a fertilizer. For years, it has been instituted as an effective fertilizer, with good water solubility and rapid dissolving abilities. Not only that, but its two molecular bases, ammonium and phosphate, are crucial minerals for the healthy and sustained growth of plants. It does this by helping the plant convert the many nutrients within the plant into “building blocks” of growth.   Ammonium polyphosphate is also used as a flame retardant in many applications such as paints and coatings, and in a variety of polymers: the most important ones are polyolefins, and particularly polypropylene, where Ammonium Polyphosphate (APP) is part of intumescent systems. Compounding with Ammonium Polyphosphate-based flame retardants in polypropylene is described in. Further applications are thermosets, where Ammonium Polyphosphate is used in unsaturated polyesters and gel coats (Ammonium Polyphosphate blends with synergists), epoxies and polyurethane castings (intumescent systems). Ammonium Polyphosphate is also applied to flame retard polyurethane foams. 
 Ammonium polyphosphates as used as flame retardants in polymers have long chains and a specific crystallinity (Form II). They start to decompose at 240 °C to form ammonia and phosphoric acid. The phosphoric acid acts as an acid catalyst in the dehydration of carbon-based poly-alcohols, such as cellulose in wood. The phosphoric acid reacts with alcohol groups to form heat-unstable phosphate esters. The esters decompose to release carbon dioxide and regenerate the phosphoric acid catalyst. In the gas phase, the release of non-flammable carbon dioxide helps to dilute the oxygen of the air and flammable decomposition products of the material that is burning. In the condensed phase, the resultant carbonaceous char helps to shield the underlying polymer from attack by oxygen and radiant heat. Use as an intumescent is achieved when combined with starch-based materials such as pentaerythritol and melamine as expanding agents. The mechanisms of intumescence and the mode of action of Ammonium Polyphosphate are described in a series of publications. 
 Ammonium Polyphosphate is a stable, non-volatile compound. In contact with water Ammonium Polyphosphate it slowly gets hydrolysed to monoammonium phosphate (orthophosphate). Higher temperatures and prolonged exposure to water will accelerate the hydrolysis. Long chain Ammonium Polyphosphate starts to decompose at temperatures above 300 °C to polyphosphoric acid and ammonia. Short chain Ammonium Polyphosphate will begin to decompose at temperatures above 150 °C. 
 There are two main families of ammonium polyphosphate : Crystal phase I Ammonium Polyphosphate (Ammonium Polyphosphate I) and Crystal phase II Ammonium Polyphosphate (Ammonium Polyphosphate II). 
 Crystal phase I Ammonium Polyphosphate (APP I) is characterized by a variable linear chain length, showing a lower decomposition temperature (aprox 150°C) and a higher water solubility than Crystal Phase II Ammonium Polyphosphate. The general structure of Ammonium Polyphosphate is given below. 
In Ammonium Polyphosphate I, n (number of phosphate units) is generally lower than 100. 
 Crystal phase II Ammonium Polyphosphate (APP II) 
As shown  below, Ammonium Polyphosphate II structure is cross linked/branched. The molecular weight is much higher than Ammonium Polyphosphate I with "n" value higher than 1000. Ammonium Polyphosphate II has a higher thermal stability (decomposition starts at approximately 300°C) and lower water solubility than Ammonium Polyphosphate I. 
 When plastic or other materials which contain Ammonium Polyphosphate are exposed to an accidental fire or heat, the flame retardant starts to decompose, commonly into polymeric phosphoric acid and ammonia. The polyphosphoric acid reacts with hydroxyl or other groups of a synergist to a non stable phosphate ester. In the next step the dehydration of the phosphate ester follows. A carbon foam is built up on the surface against the heat source (charring). The carbon barrier acts as an insulation layer, preventing further decomposition of the material. 
Addition of synergetic products like pentaerythritol derivatives, carbohydrates and spumific agents (melamine etc.) will significantly improve the flame retardant performance of Ammonium Polyphosphate. Budenheim offers pre-mixed synergistic systems, which contain an optimised mixture of Ammonium Polyphosphate II, charring and blowing agents in a well balanced formulation. 
Ammonium Polyphosphate is a branched or linear polymeric compound with a variable degree of polymerization (n). Generally, Ammonium Polyphosphate of a low degree of polymerization (n ≤ 100, crystalline form I) is water soluble or water sensitive, while Ammonium Polyphosphate with longer chains (n ≥ 1000, crystalline form II) displays a very low water solubility (<0.1 g/100 mL). In general, long-chain Ammonium Polyphosphate starts to degrade at a temperature of above 300°C, generating ammonia and polyphosphoric acid, while the short-chain one begins decomposing at 150°C. Thus choosing Ammonium Polyphosphate as the flame retardant strongly depends on the processing temperature of materials. When Ammonium Polyphosphate is added into a polymeric material containing oxygen and/or nitrogen elements, the char may form. At high temperature, Ammonium Polyphosphate degrades to create free acidic hydroxyl groups and form ultraphosphate and polyphosphoric acid, which can catalyze the dehydration reaction of polymers to yield char residues.
Ammonium polyphosphate is a non-reactive, inorganic material, that is compatible with many polymers. However, as indicated under "thermal stability", the processing temperatures limit the application of Ammonium Polyphosphate. The maximum processing temperature is 230°C. Also the Ammonium Polyphosphate should not be processed under pH >7, because ammonia will be released. Depending on the coating, the Ammonium Polyphosphate can have different pH values between 5-8. For pH sensitive application our melamine coated products can be used. Although Ammonium Polyphosphate II (FR has a very low water solubility (< 0,5 g/100 ml), in certain applications an even lower solubility is demanded. Different Coatings of Ammonium Polyphosphate can achieve lower water solubilities and a better durability under humid conditions. The FR performance is not affected by the coating. Ammonium polyphosphate Phase II has a good thermal stability > 300°C However, in combination with other chemicals (e.g. char promoter, blowing agent in intumescent mixtures) and under the mechanical stress and shear during extrusion, Ammonium Polyphosphate is limited to processing temperatures between 190 and 210°C. Under too drastic conditions decomposition of the Ammonium Polyphosphate will occur with the smell of ammonia. However, temperatures for the extrusion of PP/PE are well suited to the processing window of Ammonium Polyphosphate. With a loading of 18-25% of an Ammonium Polyphosphate based intumescent mixture, a V0 (UL 94, 1,6 mm) and thicknesses of 0.8mm can be achieved.  
FUNCTIONAL USES: Sequestrant, emulsifier 
 Application 
 Period: Autumn, Spring 
 Method: During and pre-sowing 
 Soils: All soils  
-intumescent fire-resistant coatings, for polyolefins (polypropylene, polyester and thermoplastic polyolefins)
-polyurethane foams (hard, elastic and TPU)
-thermosetting resins (epoxy, phenolic and unsaturated polyesters)
-thermoplastic, textile coatings, paints, plywood.
Ammonium polyphosphate is used as a flame retardant in many applications such as paints and coatings, and in a variety of polymers: the most important ones are polyolefins, and particularly polypropylene, where Ammonium Polyphosphate is part of intumescent systems. Compounding with APP-based flame retardants in polypropylene is described in. Further applications are thermosets, where Ammonium Polyphosphate is used in unsaturated polyesters and gel coats (Ammonium Polyphosphate blends with synergists), epoxies and polyurethane castings (intumescent systems).
Ammonium polyphosphate is a specialty chemical that finds many different uses in key industries.  
Ammonium Polyphosphate, is an environment-friendly and halogen-free flame retardant. It is the main constituent of many intumescent flame retardant systems: coatings, paints and engineering plastics. It is used to prepare 20% Phosphorous/Nitrogen containing flame retardants, it can be used solely or in conjunction with other materials in the flameproof treatment for textiles, papers, fibers and woods. Special treatment can be used to prepare 50% high concentration flameproof formulations required for special applications.
The most common ammonium polyphosphate fertilizers have a N-P2O5-K2O (nitrogen, phosphorus and potassium) composition of 10-34-0 or 11-37-0. Polyphosphate fertilizers offer the advantage of a high nutrient content in a clear, crystal-free fluid that remains stable within a wide temperature range and stores well for long periods. A variety of other nutrients mix well with polyphosphate fertilizers, making them excellent carriers of micronutrients typically needed by plants.
Ammonium phosphate, with its salt-like properties and compounds including ammonia, has use in many different areas. One of these may surprise you – it is often used in baking as a leavening agent. In this instance, the oven’s heat causes the compound to become a gas and evaporate, leaving behind an airy product with no ammonia residue. It’s even listed as an ingredient in many commercially baked products. Not only can ammonium phosphate help feed humans, but it’s used to feed plants as well. For years, it has been instituted as an effective fertilizer, with good water solubility and rapid dissolving abilities. Not only that, but its two molecular bases, ammonium and phosphate, are crucial minerals for the healthy and sustained growth of plants. It does this by helping the plant convert the many nutrients within the plant into “building blocks” of growth.  Additionally, fertilizers containing ammonium phosphate often also help in the addition of nitrogen to the surrounding soil, further aiding growth and root development. Its solubility allow for fast release into the soils, which benefits newer plants and plants in need of revitalization.
A lesser-known but equally important use of ammonium phosphate is as an ingredient in dry chemical fire extinguishers. These types are the ones usually found in high-use locations such as homes, offices and schools. This application uses the monobasic ammonium phosphate, and when sprayed on the fire, it coats the fuel source, effectively smothering the flames. Along this same line, it is also employed as a component in flame retardant-necessary applications.
Ammonium polyphosphates as used as flame retardants in polymers have long chains and a specific crystallinity (Form II). They start to decompose at 240 °C to form ammonia and polyphosphoric acid. The phosphoric acid acts as a catalyst in the dehydration of carbon-based poly-alcohols, such as cellulose in wood. The phosphoric acid reacts with alcohol groups to form heat-unstable phosphate esters. The esters decompose to release carbon dioxide and regenerate the phosphoric acid catalyst. In the gas phase, the release of non-flammable carbon dioxide helps to dilute the oxygen of the air and flammable decomposition products of the material that is burning. In the condensed phase, the resultant carbonaceous char helps to shield the underlying polymer from attack by oxygen and radiant heat therefore preventing the pyrolysis of the substrate. Use as an intumescent is achieved when combined with polyalcohols such as pentaerythritol and melamine as expanding agent. The mechanisms of intumescence and the mode of action of Ammonium Polyphosphate are described in a series of publications. Due to its uncritical toxicological and environmental profile, ammonium polyphosphate has the potential to widely substitute halogen-containing flame retardants in a series of applications like flexible and rigid PUR-foam and thermoplastics.
Compounding with APP-based flame retardants in polypropylene is described in. Further applications are thermosets, where Ammonium Polyphosphate is used in unsaturated polyesters and gel coats (Ammonium Polyphosphate blends with synergists), epoxies and polyurethane castings (intumescent systems). Ammonium Polyphosphate is also applied to flame retard polyurethane foams. Ammonium polyphosphates commercially used as flame retardants in polymers have long chains and a specific crystallinity (Form II). They start to decompose at 240 °C to form ammonia and ammonium phosphate.
Ammounium polyphosphate acts as an acid catalyst in the dehydration of carbon-based poly-alcohols, such as cellulose in wood. Ammonium polyphosphate reacts with alcohol groups to form heat-unstable phosphate esters. The esters decompose to release carbon dioxide and regenerate ammonium phosphate catalyst. In the gas phase, the release of non-flammable carbon dioxide helps to dilute the oxygen of the air and flammable decomposition products of the material that is burning. 
In the condensed phase, the resultant carbonaceous char helps to shield the underlying polymer from attack by oxygen and radiant heat.
Use as an intumescent is achieved when combined with starch-based materials such as pentaerythritol and melamine as expanding agent.
Ammonium polyphosphate (APP), as inorganic phosphorus flame retardant with nitrogen-phosphorus synergistic intumescent effect, has the advantages of thermal stability and lasting effect. APP can also improve the mechanical properties of the material, so it is often used with other flame retardants and the most common APP flame retardant studied by researchers is form II, of which the polymerization degree is greater than 1000.
Usages:
1.Used as a flame retardant for flame retardant fibers, wood, plastics, fire retardant coatings, etc
2.Used as fertilizer
3.Used as an inorganic additive type flame retardant for the manufacture of flame retardant coatings, flame retardant plastics and flame retardant rubber products
4.Used as a tissue improver; emulsifier; stabilizer; chelating agent; yeast food; pickling aid; water binding agent
5.Used in cheese

Agricultural: Relating to agricultural, including the raising and farming of animals and growing of crops        
Drug: Drug product, or related to the manufacturing of drugs; modified by veterinary, animal, or pet if indicated by source    
Food: Food for human consumption, does not include food additives also includes manufacture of food, facilities related to food (with appropriate modifiers)
Manufacturing, agrochemical: Agricultural chemicals used on a variety of crops
Manufacturing, fertilizer: Fertilizer for consumer or industrial use, and manufacturing of fertilizers
Manufacturing, pesticide: Substances used for preventing, destroying or mitigating pests
Pesticide, inert ingredient:    Inert ingredients in a pesticide
Properties:
-high degree of polymerization
-good heat resistance
-low hygroscopicity.
-This product is a highly effective inorganic flame retardant.
 Advantages 
-Enables broad time frame for application 
-Requires no moisture for dissolving due to its liquid form 
-Ensures prolonged phosphorus nutrition 
-Provides great efficiencyof a phosphate fertilizer 
-Provides efficient use in lowdoses 
-Suitable for foliar and root application
Ammonium polyphosphate is the ammonium salt of phosphoric acid. It is a high molecular weight fire retardant. To achieve a synergistic effect, ammonium polyphosphate is added to the formulation of fire retardant coatings together with pentaerythritol or melamine. ETS Group of Companies offers supplies of ammonium polyphosphate for the paint and varnish industry and the production of coatings for use in the production of such final products as:
 -intumescent fire-resistant coatings, for polyolefins (polypropylene, polyester and thermoplastic polyolefins)
-polyurethane foams (hard, elastic and TPU)
-thermosetting resins (epoxy, phenolic and unsaturated polyesters)
-thermoplastic
-textile coverings
-paints
-plywood
-Ammonium Polyphosphate Exflam APP-201
-Ammonium Polyphosphate Kylin APP-201