A kind of preparation method of segmental synthesis crystal II type ammonium polyphosphate

Abstract

The present invention discloses a preparation method for sectional synthesis of crystal II type ammonium polyphosphate. According to the method, phosphorus pentoxide is adopted as a raw material and is subjected to a two-stage reaction to obtain the crystal II type ammonium polyphosphate with the stable crystal form, wherein in the first-stage reaction, a mixture comprising one or two selected from urea and melamine is added to phosphorus pentoxide, the raw materials are uniformly mixed and are subjected to reaction polymerization at a temperature of 160-330 DEG C in a polymerization reactor so as to complete the first-stage reaction, the first-stage reaction product, phosphorus pentoxide and ammonium phosphate selected from ammonium dihydrogen phosphate and diammonium hydrogen phosphate are mixed, the second-stage reaction at a temperature of 260-350 DEG C is performed in a pressure polymerization kettle after the three materials are uniformly mixed, and cooling, material discharge and crushing are sequentially performed to obtain the crystal II type ammonium polyphosphate product with the stable crystal form. Compared with other preparation method, the crystal II type ammonium polyphosphate synthesis method of the present invention has the following characteristic that: with the simple and easy-operation two-stage reaction, the crystal II type ammonium polyphosphate product with the stable crystal form can be synthesized in a short reaction time.

Description

technical field

[0001] The invention relates to a preparation method for segmentally synthesizing crystalline type II ammonium polyphosphate. The method has low reaction temperature, easy operation, short total reaction time and stable crystal form of the obtained crystalline type II ammonium polyphosphate. Background technique

[0002] Ammonium polyphosphate (hereinafter referred to as APP), as a halogen-free intumescent flame retardant, has been widely used in various fields of the flame retardant material industry for its non-toxic, tasteless, non-toxic gas, and excellent performance. application. There are currently six known crystal forms of APP, namely type I to type VI, but only type I, type II and type V are stable crystal forms. Among the currently known stable crystal forms of APP, since type II has better water resistance, heat resistance and stability than type I, it has wider applications and better performance in flame retardant applications.

[0003] Current...

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