Method for producing type I ammonium polyphosphate with high degree of polymerization

Abstract

The invention discloses a method for producing type I ammonium polyphosphate with high degree of polymerization. The method comprises the following steps: using urea phosphate, ammonium dihydrogen phosphate and urea as raw materials, mixing, melting and foaming the raw materials, and performing a condensation reaction on the mixture in an ammonia atmosphere, wherein the mol ratio of the urea phosphate to the ammonium dihydrogen phosphate to the urea is 1: (0-5.5): (0.2-8.0), the reaction temperature is between 200 and 320 DEG C, the reaction pressure is between 0.06 and 0.12 MPa, the reaction time is between 60 and 150 minutes, reaction products are crushed to prepare the type I ammonium polyphosphate with high degree of polymerization, and ammonia-containing exhaust gas is recovered. The method is simple to operate and easy to implement with high degree of polymerization of the products, and is conducive to the popularization of industrialization.

Description

Technical field: [0001] The present invention relates to the production method of inorganic phosphorus-based flame retardant ammonium polyphosphate, in particular to the production method of high polymerization degree I type ammonium polyphosphate with urea phosphate, ammonium dihydrogen phosphate and urea as raw materials. Background technique: [0002] Ammonium polyphosphate (ammonium polyphosphate, abbreviated as APP) is an excellent flame retardant. Its phosphorus content and nitrogen content are high, so it has high flame retardant performance, good thermal stability, low solubility in water, the product is nearly neutral, and does not produce toxic and harmful gases such as chlorine and bromine during combustion. Halogen-free, low-smoke, low-toxicity environment-friendly flame retardant. [0003] For a long time, the production of I-type ammonium polyphosphate is mainly obtained by polycondensation reaction of 85% thermal phosphoric acid and urea, but thermal phosphor...

AI Technical Summary

Problems solved by technology

Since polyphosphoric acid is generally made from yellow phosphorus, there must be problems of high cost, high energy consumption, and high pollution

In addition, this method has a large heat release during the reaction process, the viscosity of the reaction system is high, and it is difficult to remove the heat. At the same time, the method has high requirements on temperature and pressure, the reaction conditions are relatively harsh, and production control is difficult, which is not conducive to industrialization.