膨胀型防火涂料炭化层形成过程的探讨

Discussion Over Forming Process of Charring Layers of Intumescent Fireproof Coating

炭化层的形成过程和最终状态是决定钢结构膨胀型防火涂料耐火极限的主要因素 ,因此 ,如何形成轻质、均匀、致密和强度高的炭化层是这类涂料研究和生产的技术关键。膨胀型防火涂料的炭化层形成过程是在高温条件下剧烈的化学反应过程 ,因此 ,涂料配方中的各个组分在这种极端的反应条件下都有可能参与炭化层的形成 ,从而最终影响炭化层的形态。本文通过对有机物体系中常用的阻燃剂———硼酸锌在膨胀型防火涂料中的不同含量对涂料耐火极限和形成炭化层的形态影响 ,得出了硼酸锌的加入对膨胀型防火涂料的炭化层具有负面影响的结论。同时 ,通过涂料配方中不同树脂的试验 ,以及添加表面活性剂对炭化层的作用等 ,得出了各组分对炭化层形态的影响规律。并用泡沫塑料膨胀过程的理论分析对上述实验现象进行解释 ,对钢结构膨胀型防火涂料的配方研制具有实际指导意义。

Forming process of charring layers and its final state were main factors to decide fireproof limit of intumescent fireproof coating for steel structure, therefore how to form light, homogeneous, tight and high strength charring layers was the key technology for study and production of such coatings. Forming process of charring layers of intumescent fireproof coatings was a severe chemical reaction process at high temperature, so it was possible for various components from the coating formulation to participate in the forming process of charring layers, hence finally influencing morphology of charring layers. In this paper, through effects of different contents of hydrated zinc borate, which was commonly used as flame retardant in polymers, in intumescent fireproof coating on fireproof limit and morphology of charring layers formed for the coating, conclusions were obtained that addition of zinc borate exerted negative effects on the charring layers of intumescent fireproof coating. In addition, by means of tests on different resins used for the coating formulation and based on effects of adding surfactants on charring layers, regularity was obtained for effects of various components on morphology of charring layers. And theoretical analysis of the expansion process of foamed plastics was made to explain the abovementioned phenomena in tests which offered practical guidance in formulation development for intumescent fireproof coating for steel structure.