摘要 |
A process for imparting flame-retardant character to cellulosic containing material has been devised in which the cullolosic material is impregnated with an aqueous solution of a tetrakis(hydroxymethyl)phosphonium compound, preferably partially neutralized tetrakis(hydroxymethyl)phosphonium chloride, the impregnated material is at least partially dried, e.g., to about 5 to 25 percent by weight moisture retention, without fixation of the phosphonium compound on the material, the partially dried material is cooled and then treated with dry ammonia gas optionally in the presence of water vapor whereby the phosphonium compound is cured on the material and a fire-retardant character is imparted thereto.
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