Preparation And Performance Of Ultra-thin Fire Retardant Coatings For Steel Structure

At present,ultra-thin fire retardant coating for steel structure has become the mainstream of fire retardant coating for steel structure.Although the ultra-thin fire retardant coatings for steel structure on the market have a very high expansion rate and foaming effect,the number of honeycomb pores in the carbon layer formed by fire is less and the pore size of pores is too large.In addition,the strength of the carbon layer is often low,and the thermal stability is not high under high temperature baking,and it is easy to decompose,produce cracks and spread cracks,so that the fireproof performance,flame retardancy and smoke suppression performance are not good for a long time.In view of the above problems,this paper prepared solvent-based and water-based ultra-thin steel structure fire retardant coatings from the point of view of the design of the basic components of fire retardant coatings.Then the synergistic effects of each component on the fire retardant and smoke suppression properties of the coatings were systematically studied,and the structure-activity relationship between the structure of the carbon layer and its fire retardant and smoke suppression properties was deeply discussed.The main research contents are as follows:(1)Based on the synergistic effect of intumescent flame redardant(IFR),filler,color base ratio and special filler,the epoxy resin based ultra-thin fire retardant coating for steel structure was designed and prepared.The influences of IFR,fillers,base ratio and special fillers on the fire retardant and smoke suppression properties of the solvent-based ultra-thin steel structure fire retardant coating were studied,and the relationship between the carbon formation properties and the structure of the carbon layer and the fire retardant and smoke suppression properties of the coating was explored.The results showed that when the proportion of IFR was IFR1:IFR2:IFR3:IFR4:IFR 5=32:15:27:8:7,the proportion of filler components was Filler1:Filler2:Filler3=68:16:20,the ratio of IFR to filler is 3:1,the ratio of skin to base is 90:63,and the optimal dosage of Filler4 is 0.065wt%,the obtained intumescence fire retardant coating(IFRCA35)had the best fire resistance and smoke suppression performance.The fire resistance rating of IFRCA35 reaches Ft3.00.PHRR,THR,TSP and TOC of IFRCA35 were218.09k W/m~2,38.84MJ/m~2,8.49m~2 and 24.55g,respectively,which decreased by 90.9%,42.64%,59.9%and 45.4%compared with the sample prepared by epoxy resin and its supporting curing agent(IFRCA0),respectively.IFRCA35 has good carbon formation performance and the carbon residue rate is up to 32.1%.The carbon layer has high strength,good heat insulation effect,and thermal conductivity is only 0.021 W/(m·?).(2)In order to obtain more environmental protection fire retardant coating,water based ultra-thin steel structure fire retardant coating was further developed.The water-based ultra-thin fire retardant coating for steel structure was prepared by designing and optimizing the dispersive medium,special filler,expansion flame retardant system and filler ratio,etc.The fire retardant and smoke suppression performance of the fire retardant coating were comprehensively evaluated,and the influence law of the carbon formation performance and the structure of the carbon layer on the fire retardant and smoke suppression performance was explored.The results show that when the dosage of dispersive medium is 29wt%,Filler4 is0.167wt%,and the ratio of IFR to filler is 3:1,the obtained intumescence fire retardant coating(IFRCB13)has the best fire resistance and smoke suppression performance.The fire resistance rating of IFRCB13 reaches Ft3.00.The PHRR,THR,TSP and TOC of IFRCB13 were161.44k W/m~2,12.58MJ/m2,1.06m~2 and 7.85g,respectively,which were reduced by 88%,72.2%,87.9%and 73.2%compared with the sample prepared by pure acrylic resin(IFRCB0),respectively.IFRCB13 has good carbon formation performance and the carbon residue rate is up to 42.36%.The carbon layer has high strength,good heat insulation effect,and thermal conductivity is only 0.029 W/(m·?).