| abstract |
A fire-retardant composition for rendering a combustible hydrophilic substrate resistant to combustion and flaming is disclosed. Also disclosed are processes employing said composition for rendering a hydrophilic substrate resistant to combustion, as well as structural material made fire-resistant by such a process. The composition is a thermoset formed by combining two resins, which can be either made and stored separately for long periods until use or stored as a partially polymerized liquid mixture. The resins are water soluble and heat-curable to form the thermoset. The first resin comprises polyols derived preferably from a carbohydrate such as maltodextrin having substituent groups occupying a portion of the available hydroxyls derived from monoammonium phosphate, urea, phosphoric acid, and glyoxal. The second resin can be a methylol-melamine-formaldehyde, methylol-urea-formaldehyde, or methylol-phenol-formaldehyde formulation. When cured on a hydrophilic substrate, the fire-retardant composition becomes crosslinked and covalently bonded to molecules of the substrate. Also, P- and N-containing consituents critical for fire retardancy are covalently bound in the thermoset, rendering these constituents non-leachable. As a result, fire-retardancy is maintained throughout the useful life of the substrate, even when exposed to the weather. |