Microencapsulated red phosphorus

摘要

A method for preparing encapsulated red phosphorus is disclosed. The method entails obtaining a material system that contains dispersed particulate red phosphorus having a mean particle size of 0.1 to 100 mum in an aqueous phase that comprise urea, formaldehyde and a water-soluble silicon dioxide precursor, adding to the material system a sufficient amount of acid to lower the pH to 0 to 5 and maintaining the resulting acidic system at a temperature of 80 to 120° C. for a period longer than one hour. The encapsulated red phosphorus of the invention is suitable for using as a flame retarding agent for plastics molding compositions.