Production and use of fire retardant dispersions as additives for building panels

A fire retardant panel prepared from a thermosetting resin selected from the group consisting of polyesters, polyepoxy resins, and polyurethane resins and containing reinforceable fibers embedded therein, the fire retardant properties of said panel being improved by the distribution in said panel of about 3 to about 10 percent by weight of said resin of a substantially inert fire retardant blend comprising at least about 25 percent by weight of a solid organic halogen-containing material, about 10 to about 30 percent by weight of a solid inorganic synergist, and about 20 to about 35 percent by weight of a liquid organic phosphoric carrier, said solid halogen-containing material includes an aliphatic compound wherein at least the majority of the weight of the aliphatic compound is a halogen selected from the group consisting of bromine, chlorine and mixtures thereof, said inorganic synergist is selected from the group consisting of antimony metal, antimony compounds, boron compounds and mixtures thereof, said fire retardant blend consisting essentially of solid particles having a particle size up to 20 microns.

The process of preparing a fire retardant panel comprising the steps of preparing a blend of a thermosetting resin and fillers, maintaining the blend at a temperature at which the blend has a flowable viscosity, catalyzing the resin, flowing the resin onto a moving carrier film, embedding reinforcing fibers into the resin layer, applying a second film layer on top of the resin, and curing the resin, the improvement comprising adding about 3 to about 10 weight percent of a substantially inert fire retardant to the blend before catalyzing the blend, said fire retardant comprising a dispersion including at least about 25 weight percent of a solid halogen-containing organic molecule, about 10 to about 30 weight percent of a solid inorganic synergist, and about 20 to about 35 weight percent of a liquid organic phosphate, said dispersion processed prior to addition to the blend to produce particles having a size distribution up to about 20 microns, said halogen-containing organic molecule consisting of at least 50 weight percent of a halogen selected from the group consisting of bromine, chlorine and mixtures thereof, said inorganic synergist including a solid selected from the group consisting of antimony metal, antimony compounds, boron compounds and mixture thereof.