Preparation method of assistant with flame-retardant and antimicrobial functions

The invention relates to a preparation method of an assistant with flame-retardant and antimicrobial functions, which comprises the following steps: dissolving dicyandiamide, adding a proper amount of hydrochloric acid solution, adding diethanolamine, uniformly stirring, reacting for some time to obtain a milk-white semitransparent liquid, adding water, and adding phosphorus pentoxide to react to obtain a light-yellow viscous liquid which is the assistant with flame-retardant and antimicrobial functions. The assistant with flame-retardant and antimicrobial functions can be used for functional finishing of pure cotton fabrics to endow the cotton fabrics with the flame-retardant and antimicrobial functions; and the prepared assistant is safe and environment-friendly, and is a novel functional assistant.