膨胀型防火涂层“新-老”涂层体系的热阻  

Thermal resistance of“aging-fresh”coating of intumescent coatings

作　　者：王玲玲[1] 刘天蛟 朱鑫 李国强[2] WANG Ling-Ling;LIU Tian-Jiao;ZHU Xin;LI Guo-Qiang(College of Civil Engineering,Huaqiao University,Xiamen 361021,China;College of Civil Engineering,Tongji University,Shanghai 200092,China)

机构地区：[1]华侨大学土木工程学院,厦门361021 [2]同济大学土木工程学院,上海200092

出　　处：《四川大学学报（自然科学版）》2024年第4期251-257,共7页Journal of Sichuan University(Natural Science Edition)

基　　金：国家自然科学基金面上项目(51778250);福建省自然科学基金面上项目(2022J01289)。

摘　　要：在既有老化涂层上涂覆新涂层形成“新-老”复合涂层体系,复合涂层的热阻并非既有涂层热阻与补涂涂层热阻的简单叠加.基于隔热性能试验的温度测量结果,计算复合涂层体系的等效热阻常数,通过对不同试件等效热阻常数的对比分析,考察补涂涂层对既有涂层和复合涂层热阻的影响规律.结果表明:既有涂层热阻随补涂涂层厚度增加而降低,当补涂涂层厚度大于1.0 mm时,既有涂层热阻的贡献率不超过20%,计算复合涂层热阻时可忽略不计;当补涂涂层厚度较薄(0.5 mm)且既有涂层老化时间较短(≤21循环),或既有涂层有面漆时,建议考虑既有涂层热阻的贡献(贡献率>20%).当补涂涂层与既有涂层类型不同时,复合涂层体系的热阻更大,隔热性能更好.The formation of the“aging-fresh”composite layer in intumescent coatings involves the application of a new coating onto an existing coating.It is important to note that the thermal resistance of this composite layer cannot be simply calculated by superposing the thermal resistance of the two individual coatings.In order to determine the constant effective thermal resistance of these composite layers,fire tests were carried out.The aim of these tests was to investigate the impact of recoating on the thermal resistance of the existing coating and the resulting composite layer.A comparative analysis was conducted on the constant effective thermal resistances of various specimens.The results of the analysis indicate that the thermal resistance of the existing coating decreases as the thickness of the recoated coating increases.Additionally,when the thickness of the recoated coating exceeds 1.0 mm,the contribution rate of the thermal resistance from the existing coating does not surpass 20%.Therefore,it can be disregarded when calculating the thermal resistance of the composite layers.However,in cases where the recoated coating is thin(e.g.,0.5 mm)and the existing coating,without a topcoat,has undergone moderate environmental aging(e.g.,fewer than 21 cycles of aging test),or when the existing coating has a topcoat,the contribution of the existing coating becomes significant(with a contribution rate exceeding 20%).Moreover,the utilization of a new coating type different from the existing one results in higher thermal resistance and enhanced insulation properties of the composite layer.

关 键 词：膨胀型钢结构防火涂层 补涂 复合涂层 隔热性能 等效热阻常数 

分 类 号：TU545[建筑科学—建筑技术科学]