面漆对湿热环境下膨胀型防火涂层隔热性能的影响

Effect of Topcoat on Insulation Properties of Intumescent Coatings under Hydrothermal Environmental Condition

通过105个试件的湿热老化试验和隔热性能试验,研究了2种面漆对膨胀型钢结构防火涂层耐湿热老化性能和隔热性能的影响.结果表明:在经过84次湿热老化循环后,无面漆试件等效导热常数比未老化试件增大131%,涂有2层E型和A型面漆试件的等效导热常数分别比未老化试件增大42%和21%,面漆降低了湿热环境对膨胀型钢结构防火涂层导热系数的影响,涂层隔热性能提高;面漆抑制了涂层膨胀,膨胀层隔热性能降低;当老化时间较短时,面漆对涂层膨胀的抑制作用大于其对涂层耐老化性能的提高,总体上降低了涂层的隔热性能;随着老化时间的延长,面漆的正向作用逐渐显现;膨胀型钢结构防火涂层的隔热性能随面漆厚度的增加而增大.

Accelerated hydrothermal aging test and fire test of 105 intumescent coating protected steel specimens were conducted to investigate the effect of two types of topcoat on anti-aging and insulation properties of intumescent coating for steel elements.The results show that compared to specimens without aging,the constant effective thermal conductivities of specimens after 84 cycles of hydrothermal aging test but without topcoat increases by 131%.Applying topcoat reduces the effect of aging and the constant effective thermal conductivities of specimens after 84 cycles but with 2 layers of type E topcoat and two layers of type A topcoat increases by 42%and 21%respectively.Applying topcoat can also limit expansion of intumescent coating.When intumescent coating experiences prolonged cycles of aging test,the protective effect of topcoat prevails and using topcoat can increase insulation properties of intumescent coating.Otherwise,using topcoat will result in worse properties of intumescent coatings.