| abstract |
An intumescent water-based coating comprises 43.13-52.71 wt.% water, 0.89-1.09 wt.% water soluble polycarboxylate, 0.134-0.164 wt.% biocide, 0.18-0.219 wt.% antifoam, 2.68-3.28 wt.% colloidal silica, 8.95-10.95 wt.% polyester resin, 0.90-1.09 wt.% hydroxy ethyl cellulose, 14.33-17.51 wt.% ammonium polyphosphate, and 18.81-22.99 wt.% polyurethane resin. Preferably, the composition comprises 47.917 wt.% water, 0.99 wt.% water soluble polycarboxylate, 0.149 wt.% biocide, 0.199 wt.% antifoam, 2.98 wt.% colloidal silica, 9.95 wt.%. polyester resin, 0.995 wt.% hydroxy ethyl cellulose, 15.92 wt.% ammonium polyphosphate, and 20.9 wt.% polyurethane resin. Typically, the water soluble polycarboxylate acts as a suspension aid, the colloidal silica functions as a nucleating agent, the polyester resin acts as a char enhancer, the hydroxy ethyl cellulose acts as a thickener, the ammonium polyphosphate acts as an acid donor, and the polyurethane resin acts as a binder. The coating may be used for internal and external timber surfaces. |