| abstract |
A synthetic polymer foam is produced which incorporates fine particles of expandable graphite which surprisingly impart excellent fire resistant properties to the foam, particularly to foam made with a non-halogenated hydrocarbon as the primary blowing agent. For best results, the foam is produced through mixing the constituent materials, including the expandable graphite using a screw extruder. The foam can also be produced by creating a graphite/polyol or graphite/isocyanate dispersion in an extruder then mixing the remaining components in a conventional batch mixing or high pressure spraying process. Alternatively, conventional mixing can be used for the entire process, but use of a screw extruder in whole or in part is preferred. |