| As the applications of steel in building construction become wider and wider, its fire protection is of great significance. Water-based ultra-thin steel structure fire-resistant coating is becoming the direction and trend of the fire retardant coating as it is finer and thinner, simpler and more convenient, easy construction, environmental security, and so on.This paper studied the formula and synthetic conditions of epoxy modified acrylic latex; synthesized styrene-acrylic emulsion; studied the fire-resistant properties of the fire-refractory coating with styrene-acrylic latex and epoxy modified acrylic emulsion as base, and APP, PER, MEL as expansion. Studied the influence of the expanded graphite and magnesium hydroxide as flame retardant additives on fire properties of coating,the titanium dioxide and talc as inorganic filler on the coating properties, and confirmed the optimum process conditions. The structure of the film-forming compounds detected with IR; the fireproof limit was measured by vertical burning method; the thermal stability of coating was investigated by thermogravimetry. The thermodynamic model of coating was established and the activation energy was calculated. Other properties of fire retardant coating detection based on national standard.The results showed that in the process of epoxy-modified acrylic emulsion synthesis, 2/1 was the optimum mass rate of OP-10/DBS, and the total volume of OP-10 and DBS was 4.5% of the monomer consumption. 0.5% was the optimum mass rate of initiator / monomer, 80℃(±2℃) was the optimum reaction temperature, epoxy resin dosage was 8%, the optimum proportion of soft and hard monomers was 1.8/1.0, 105/50 was the optimum ratio of water and monomer, and the performance measure up to GB/T20623-2006. In the process of fire-resistant coating, 1/2 was the optimum mass rate of styrene-acrylic emulsion/epoxy-modified acrylic emulsion, with the dosage of 25%; 5/2/3 was the optimum mass rate of APP/PER/MEL, with the dosage of 50%; the best filler amount was 10%, inorganic flame retardants of the optimum dosage was 2%; coating thickness was 2.5 mm. at this time, the fire resistance of fire-resistant coating limit was 98min. Coating dry time was 1.5h, adhesion was one, and water-resistant meet the requirements. The results of DTA showed that fire-resistant coating was better thermal stability. The analysis of dynamics showed that the activation energy of fire-resistant coating to achieve 236.5kJ/mol; low reactivity, fire-resistant performance, measured with the experimental results that were consistent with the fire resistance test.The results shows that carbon coating layer was foaming fast and whole, density uniformity, strength, structural integrity. The expansion system and inorganic flame retardants, fillers have variety of sources, easy to get, and had a good performance with the base material; waterborne coatings and halogen-free fire retardants used in compliance with environmental requirements.
|
PDF Full Text Request