Preparation Of Silicone-acrylate Emulsion Ultrathin Steel Structural Fireproofing Coating

For high efficiency of fireproofing, decoration and facilitation of using, Ultra-thin steel structure fire retardant coating has been on a wide range of application in recent years. In order to further improve the coating's weather resistance and environmental friendliness, the application of silicone-acrylic resin and inorganic flame retardant has became popular.The synthetic process of high siloxane content silicon-acylate latex was discussed, in which the main factors that affect the stability of the reaction were determined.The composition and properties such as viscosity, particle size and its distribution were characterized. With the application of the silicon-acylate latex the improvements of the coating's expandability, fire-proofing and water resistance were investigated. Expanded graphite(EG), nano-Mg(OH)2 were introduced into the system, and we studied the effects on the fireproofing. Beside that we also modified the Expanded graphite (EG) and nano-Mg(OH)2 with Silane coupling agents to improve their consistency with other components. The thermal stability of the flame retardant coating was analysed by TG-DTA and the thermal decomposition process was discussed in kinetics.The results show that by semi-continuous emulsion polymerization, the reaction stability and general performances of silicone-acylate latex are excellent when contents of surfactants, initiator and electrolyte get to 2.0%,0.75% and 0.2% of total monomers respectively and the ration of sodium dodecyl benzene sulfonate(SDS) to OP-10 is 1.0:1.0. The fire-resistant tests prove that silicone-acrylate emulsion's applycation enhance the strength and oxidation resistance of the carbon layer. The water-resistant test confirms that the water absorption of the latex film is reduced when the siloxane monomer has been imported. And the optimal amount rate of siloxne is 10% with the consideration of the the coating's mechanical property.Using the single-factor analysis and orthogonal design fire-resistant tests gained the best condition as follows: the ratio of latex/ammonium polyphosphate/pentaery- thritol/melamine is 7.7:5.7:2.4:2.3, the proper dosage of Expandable Graphite and nano hydrogen Magnesium are 8.2% and 1.1% of the total flame retardant. The fire resisting time can reach 102.5 min with compact and high strength carbon layer.The best coupling agent were DB-151 and DB-550 for Expandable Graphite and nano hydrogen Magnesium respectively through fire-resistance test. By comparing the carbon layers, we found that it was more complete and the adhesion gets more enhanced.TG-DTA analyses show that the thermal docomposition course may be devided into four stages. The first stage can be described as one order chemistry reaction, the second stage accords with one dimensional diffuseness reaction, the last two stages can be described as 1.5 order chemistry reaction and the pyrolysis parameterts and equations of kinetics are figured out.