The flame retardant effect of fire-retardant coating of expansive steel structure is the result of organic coordination through chemical reaction of various components. The principle of flame retardant insulation is realized mainly through the following methods: (1) dehydration into carbon catalyst such as ammonium phosphatide and so on; (2) polyhydroxyl carbonizer, such as pentaerythritol, is decomposed into carbon in high temperature and acid catalysis. (3) the polymeric substrate is fused with heat and expanded by the action of the foaming agent, such as melamine, which further forms the carbonation layer.
Expansion of steel structure under the circumstance of fire, the fire retardant coating thickness of its rapid expansion to the original a few times, up to two hundred times, the formation of honeycomb or spongy carbon layer of steel fire prevention role can be summarized as three aspects: (1) the barrier, the expansion of the highly carbonized layers can be protected by steel structure have good air, heat isolation effect, so as to effectively reduce the surface temperature of steel structure, prolong the time to support the steel structure in fire; (2) the endothermic effect, softening and melting of the polymer coating, expansion after the carbonized layers and physical changes of thermal decomposition of each composition, evaporation and carbonized all can absorb a lot of heat, so as to effectively reduce the surface temperature of steel structure; (3) termination combustion and thermal decomposition of components coating of all kinds of non-combustible gases can have the effect of dilution of oxygen concentration, and from the burning of can capture free radicals, thus effectively prevent burning. The coordination function of these three processes finally makes the expansion steel structure fire retardant coating effective fire protection.
After years of development, the expanded steel structure fire retardant coating has achieved some results, and some products have already started commercial production. However, problems and deficiencies remain, and there are still many unknown areas to explore. In the future, the expansion steel structure fire retardant coating will be developed in the following aspects:
(1) to improve environmental stability, specifically, expansion of steel structure fire retardant coatings not only has good fireproof performance, more should have good environmental stability, and its properties, such as chemical corrosion prevention, prevent ultraviolet light directly affect the service life. Therefore, the environmental stability is the important research emphasis of the fire-resistant coating of the current expansion steel structure.
(2) environmental friendly expansion steel structure fire retardant paint will also be a new selling point. With the improvement of people's quality of life, the toxicity of the chemical toxicity of fire retardant coating itself and the toxicity generated from combustion are important aspects to be considered in future research.
(3) improve the fire resistance, fire retardant coating it is all important performance, the pursuit of expansion of fire resistance of steel structure fire retardant coating to improve more one minute, the protection of people life and property is more, thus improving the performance of refractory will always is the key of the research;
(4) the development of nano modified expansive steel structure fire retardant coating, it is a coating modification direction recently, disperses inorganic functional nano particles in the coating, the coating will be much better than the improvement of the performance of the fire with common inorganic nanoparticles, in order to gain high performance steel structure fire retardant coating.
