Thermally-protective intumescent coating

摘要

PCT No. PCT/US95/09761 Sec. 371 Date May 19, 1997 Sec. 102(e) Date May 19, 1997 PCT Filed Aug. 1, 1995 PCT Pub. No. WO96/03854 PCT Pub. Date Feb. 15, 1996An intumescent coating system and method therefor is disclosed for thermally protecting a substrate having a surface exposed to fire conditions. The coating system of the present invention is provided as having a first component which forms a rigid carbonific char foam having toughness and rigidity, and a second component which forms an insulative carbonific char foam having a density about half the density of the rigid carbonific foam to give insulation properties. The two foam components may be separately provided in a laminate-type arrangement as, respectively, an inner coating layer coated and cured on the surface of the substrate to form an inner film layer, and an outer coating layer coated and cured on the inner film layer to form an outer film layer. Alternatively, the two foams may be provided as being formed from components blended to comprise a single coating layer which is coated and cured on the surface of the substrate to form a film layer. In providing two foam components, one protecting the substrate from breakthrough and direct exposure to the fire conditions, and the other insulating the substrate to protect it from conductive, radiant, and/or convective heating by the fire conditions, the present invention affords a capability to offer flame retardancy at film thicknesses of less than 1.27 mm (50 mils).