Melamine-coated ammonium polyphosphate

- Dec 05, 2018-

 A  melamine-coated ammonium polyphosphate exhibiting properties of  having no hygroscopicity, being difficultly soluble in water and difficultly  susceptive of hydrolysis is provided and further a process for producing a  melamine coated ammonium polyphosphate having the above properties  and also being powdery even when it is not ground is provided, the above  powdery, melamine-coated ammonium polyphosphate being characterized in that  melamine is added and/or adhered onto the particle surface of a powdery, ammonium polyphosphate expressed by the formula  ##STR1## wherein n represents an integer of 20 or more, and a process for  producing a powdery, melamine-coated ammonium polyphosphate being characterized in that  melamine is sublimated and added and/or adhered onto the particle surface of a  powdery ammonium polyphosphate.   


1. A powdery ammonium polyphosphate having a surface which is  uniformly coated with melamine, comprising a powdery ammonium polyphosphate, having melamine added  and/or adhered uniformly onto a particle surface thereof, expressed by the  formula ##STR4## wherein n represents an integer of 20 or more, said  powdery ammonium polyphosphate being substantially free of  secondary agglomeration and having a water solubility in 10 wt % aqueous  suspension of no more than about 6.6 at room temperature.   


2. A powdery ammonium polyphosphate according to claim 1 wherein  the quantity of melamine coated is 0.5 to 20% by weight based upon the weight of  the powdery ammonium polyphosphate.  


3. Powdery ammonium polyphosphate according to claim 1 wherein  the quantity of melamine coated is 2 to 10%, by weight, based upon the weight of  the powdery ammonium polyphosphate.   


4. A powdery ammonium polyphosphate according to claim 1 wherein  said powdery ammonium polyphosphate contains less than the  stoichiometric amount of ammonia.  


 5. A powdery ammonium polyphosphate having a surface which is  uniformly coated with melamine, comprising a powdery ammonium polyphosphateexpressed by the  formula ##STR5## wherein n represents an integer of 20 or more, having melamine  added and/or adhered onto a particle surface thereof by sublimating melamine at  a temperature of 250° C. to 300° C., said powdery ammonium polyphosphate being substantially free of  secondary agglomeration and having a water solubility in 10 wt % aqueous  suspension of no more than about 6.6 at room temperature.   


6. Powdery ammonium polyphosphate according to claim 5 wherein  the quantity of melamine coated is 0.5 to 20%, by weight, based upon the weight  of the powdery ammonium polyphosphate.   


7. Powdery ammonium polyphosphate according to claim 5 wherein  the quantity of melamine coated is 2 to 10%, by weight, based upon the weight of  the powdery ammonium polyphosphate.   


8. A powdery ammonium polyphosphate according to claim 5 wherein  said powdery ammonium polyphosphate contains less than the  stoichiometric amount of ammonia.   


9. A powdery ammonium polyphosphate having a surface which is  uniformly coated with melamine, comprising a powdery ammonium polyphosphateexpressed by the  formula ##STR6## wherein n represents an integer of 20 or more and having  melamine ionically bonded to a particle surface thereof, said powdery ammonium polyphosphate being substantially free of  secondary agglomeration and having a water solubility in 10 wt % aqueous  suspension of no more than about 6.6 at room temperature.  


 10. Powdery ammonium polyphosphate according to claim 9 wherein  the quantity of melamine coated is 0.5 to 20%, by weight, based upon the weight  of the powdery ammonium polyphosphate.  


 11. Powdery ammonium polyphosphate according to claim 9 wherein  the quantity of melamine coated is 2 to 10%, by weight, based upon the weight of  the powdery ammonium polyphosphate.   


12. A powdery ammonium polyphosphate according to claim 9 wherein  said powdery ammonium polyphosphate contains less than the  stoichiometric amount of ammonia.