Preparation method of crystallization II-type ammonium polyphosphate with high degree of polymerization

Abstract

The invention relates to a preparation method of crystallization II-type ammonium polyphosphate with high degree of polymerization, the specific steps are as follows: taking diammonium phosphate as original material, taking urea and (or) melamine as condensation agent, reacting for 30-120 minutes in the temperature range of 120-320 DEG C, introducing ammonia gas to aminate for 30-100 minutes till curing and crystallization, then crushing to obtain crystallization II-type fork chain ammonium polyphosphate. The invention has the advantages that: the apparent viscosity of the product is much larger than that of the existing industrial product with average degree of polymerization being up to 1000, the degree of polymerization is generally 1500-2000, the thermolabile temperature is more than 275 DEG C, and the water solubility is less than 0.25g/100ml.

Description

【Technical field】

[0001] The invention relates to the technical field of ammonium polyphosphate preparation, in particular to a method for preparing crystalline type II ammonium polyphosphate with a high degree of polymerization. 【Background technique】

[0002] Ammonium polyphosphate (referred to as APP) molecular formula (NH 4 ) n+2 P n o 3n+1 , the phosphorus content is 30-32%, and the nitrogen content is 14-16%. Hydrogen halides are not produced. APP has good thermal stability, the product is close to neutral, and can be mixed with other flame retardants. It has good dispersibility, smoke elimination, low toxicity, and is safe to use. Therefore, it is widely used in the preparation of intumescent flame retardants, fireproof coatings, Fireproof treatment of cables, flame retardancy of rubber and plastic products.

[0003] According to the degree of polymerization, APP can be divided into short chain (n=10~20), also known as water-soluble APP; long chain (n>20), al...

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