Composition and process for imparting fire retardant properties and improved thermal stability to cellulosic materials

摘要

A process is provided for forming a fire retardant composition useful for treating cellulosic materials to impart both fire retardant properties and improved thermal stability under high temperature and humidity conditions. The process comprises reacting a solution of orthophosphoric acid, urea and water having a weight ratio from about 0.1 to about 15 orthophosphoric acid per part urea for a time of about 15 minutes to about 3 hours at a temperature from about 25 DEG C. to about 90 DEG C.; adding hydroxide in an amount sufficient to adjust the pH of the solution from about 6.0 to about 9.0; reacting the solution with formaldehyde having a weight ratio from about 1.0 to about 56 total initial orthophosphoric acid per part formaldehyde for a time of about 5 minutes to about 1.5 hours at a temperature from about 25 DEG C. to about 90 DEG C., and adjusting the final pH of the solution from about 7.0 to about 8.5 with ammonium hydroxide. In another aspect thereof, the present invention provides a method of treating cellulosic materials comprising impregnating the cellulosic material with a fire retardant amount of the fire retardant composition formed in accordance with the above process.