Among the many fire protection measures for steel structures, applying fire retardant coatings is the most economical and effective method
Water-based intumescent fire retardant coatings are green and environmentally friendly fire retardant coatings with water as the dispersing medium, and have good application prospects
At present, the water-based intumescent fireproof coatings on the market mainly use acrylic emulsion as film-forming material, and use ammonium polyphosphate (APP, carbon-forming catalyst), pentaerythritol (PER, carbon-forming agent), melamine (MEL, foaming agent) as a barrier In the combustion system, when heated, the film-forming material melts and becomes soft, the carbon-forming agent is dehydrated into carbon under the action of the catalyst, and the carbonized material and the molten film-forming material are formed under the action of the gas generated by the thermal decomposition of the foaming agent.
A layer of expanding carbon that forms a thermal barrier between the heat source and the steel, preventing heat transfer to the substrate .
Coatings Online coatingol.
If the intumescent carbon layer of the water-based intumescent fireproof coating is not strong enough, it will fall off the steel surface during the fireproofing process, which will cause the steel structure to lose its bearing capacity quickly when exposed to the flame
Pigments and fillers are an important part of water-based intumescent fireproof coatings, which play an important role in improving the fire resistance of the coating, especially the strength and stability of the carbon layer
Studies have shown that titanium dioxide is one of the few pigments that can react with ammonium polyphosphate at high temperature to improve the fire resistance of coatings
Wang Qinghai et al.
selected titanium dioxide as the reinforcing pigment, selected kaolin, aluminum hydroxide, aluminum silicate fiber, and montmorillonite to compound it, and investigated the effects of different pigments and fillers on the strength of the carbon layer and the fire resistance of the coating.
The results show that: (1) The addition of titanium dioxide can improve the ablation resistance of water-based intumescent fireproof coatings.
When the addition of titanium dioxide is 10%, the carbon layer is dense, high in strength, and has the best fire resistance
(2) Comparing the four inorganic fillers and their mixed fillers with a mass ratio of 1:1, the mixed filler with a mass ratio of kaolin and aluminum hydroxide of 1:1 has a good synergistic flame retardant effect;
(3) When the mixed filler content of 1:1 mass ratio of kaolin and aluminum hydroxide is 5%, the strength of the carbon layer and the state of the carbon layer can be significantly improved, the expansion ratio of the coating is 31 times, and the fire resistance is the best