|
Ammonium polyphosphate (APP) has 6 crystals,only 1 andⅡ-APP are in the industrial application. In literature, crystal transformation method was used to synthesizeⅤ-APP for about 20h at high temperature and got low yield, which severely limited its industrial production. Watanabe pointed out that in PP added 5-10%Ⅴ-APP can reach 30%Ⅱ-APP flame retardant effect. Therefore the development of new technology forⅤ-APP scale production, and determination its performance are significant.In this paper, phosphoric acid and ammonium phosphate were used as raw materials, melamine (MEL), urea etc as condensation agent, successfully explored 10 processes to prepare V-APP, through comprehensive properties comparison, diammonium phosphate and MEL technology was the optimal process for 5L kneader pilot production. In experiment,Ⅴ-APP converted toⅠandⅡ-APP for 1h at 110℃, indicated that temperature was important factor to control the crystal type. In addition, from 500ml flask to 5L kneader expandable production explored two step method in solving the corrosion problem for successful implementation ofⅤ- APP trial production, laid the foundation for industrialized production.
|