Method for preparing microencapsulated ammonium polyphosphate

Abstract

The invention discloses a preparation method for encapsulating ammonium polyphosphate by microcapsules; in a reaction kettle of a stirring and reflux device, the powder of the ammonium polyphosphate is suspended and dispersed in a solvent; then bisphenol A epoxy resin is added; an amine curing agent is added in a dropping mode under the situation that the solvent is a little boiled and is stirred for 2 to 10 hours to solidify the epoxy resin, then the mixture is filtered; the filter product is further solidified and dried under 90 to 120 DEG C under a nitrogen environment, thus obtaining the ammonium polyphosphate capsulated by microcapsules. Compared with the ammonium polyphosphate which is not capsulated, the free-running property of the particles of the ammonium polyphosphate prepared by the invention is good; the compatibility with a high polymer is improved; the water-solubility of the particles is greatly reduced; the electric property is obviously improved; the ammonium polyphosphate capsulated by the microcapsules can be used as the flame retardants of polymer materials such as polyolefine, and the like.

Description

technical field [0001] The invention relates to the technology of using ammonium polyphosphate as the core material and wrapping it in microcapsules, in particular to a preparation method of ammonium polyphosphate wrapped in microcapsules. Background technique [0002] The general formula of ammonium polyphosphate (hereinafter referred to as APP) is (NH 4 ) n+2 P n o 3n+1 , when n is large enough, it can be written as (NH 4 PO 3 ) n . The relative molecular weight of the structural unit is 97.01, the theoretical phosphorus content is 31.92%, and the theoretical nitrogen content is 14.44%. [0003] APP is usually a fluid powder object with high phosphorus and nitrogen content, and there is a P-N synergistic effect between them, so it has high flame retardant performance. It has good thermal stability, and the product is close to neutral. It can be compounded with many other flame retardants to improve its flame retardant performance. It has little smoke and low toxici...

AI Technical Summary

Problems solved by technology

[0005] However, Type II APP still has some disadvantages: on the one hand, because Type II APP is still an inorganic compound, it has a large amount of addition and has poor compatibility with organic polymers; on the other hand, due to the presence of oxygen bonds in the chemical structure of ammonium polyphosphate, And the oxygen bonds are often arranged on the outer surface, forming easy-absorbing water molecules, causing APP to have a certain hygroscopicity. When stored in the air, it will absorb moisture in the air, causing APP to gradually undergo hydrolysis reactions. At the same time, the addition of APP often changes the material. Under the condition of high relative humidity, water vapor penetrates into the APP flame retardant material, so that the APP in the bulk phase dissolves and migrates outward, causing the material to "white frost", the flame retardancy of the material is not durable and the electrical performance Bad and other issues

However, due to the good alcohol solubility of the wrapping epoxy resin and curing agent, the cured wrapping layer is also partially alcohol-soluble, resulting in defects in the wrapping efficiency and the compactness of the wrapping layer.

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