水性基料在超薄型钢结构防火防腐涂层体系构建中的应用

Application of Waterborne Binders in Ultra-Thin Fire Retardant Anticorrosive Coatings for Steel Structures

探讨了市面上不同树脂水分散体作为超薄型钢结构防火防腐涂料基料的可能性,通过长时间浸泡涂层考察各水性树脂的耐水性、涂层致密性以及填料溶失程度,结果表明:水性基料不适用于含有水溶性填料的单涂层体系。通过热重分析对比发泡填料体系和各树脂的热降解行为,选择热降解温程较为相似的乙酸乙烯酯共聚物和环氧共聚物作为优化涂层防火功能的主要基料。通过垂直燃烧实验测试被涂覆试样的背板温度,优化了防火涂层的颜基比;并通过调整基料复配比例,使得涂层在灼烧后可以得到膨胀厚实且粘附稳定、致密均匀的发泡层。以此为基础,构建了防腐—防火—封闭的多层防火防腐体系,该体系具有良好的耐腐蚀性及耐火性,尤其是长期浸泡后的可持续耐火性与溶剂型同类产品相当。

Current ultra-thin fire retardant anticorrosive coatings for steel structures mainly use solvent-based resins as their binders. In this paper, the feasibility of commercial available waterborne binders applied in this field is discussed. Water resistance, film density and disso- lution loss of the films based on waterborne binders are investigated by long-time immersion tests, indicating that these binders are inappropriate for single-layer coating containing soluble fillers. Thermogravimetric analysis is conducted to compare the thermal degradation of foaming system and the binders, and the results show that vinyl acetate copolymers and epoxy resins having similar degradation temperature ranges present better performance when applied in coatings. Ratio of the binders, and their amount in the formula were optimized, by which the thick, compact and uniform char-layer chars that stick to the base can be obtained after the vertical burning tests on the painted plates. On these basis, the multilayer system featuring anticorrosive/fire retardant/seal triple layers is established, which demonstrates outstanding fireretardant anticorrosive properties as compared to its solvent-based counterparts, especially after the long-time immerse test.