多指标正交实验分析在膨胀型钢结构防火涂料中的应用

Application of Orthogonal Experiment Design and Multi-index Range Analysis in Intumescent Flame-retardant Coatings for Steel Structure

采用多指标正交实验分析,对防火涂料中的膨胀阻燃体系——密胺树脂包覆聚磷酸铵MF-APP/季戊四醇笼状磷酸酯PEPA/三聚氰胺MEL体系,进行优化。首先对防火涂料配方进行正交实验设计,然后使用模拟大板燃烧法对涂料的防火性能进行测试,使用包括钢板背温平台初始温度(T1)、钢板背温到达平台所需时间(t)、30 min时所达钢板背温(T2)、膨胀倍率(H)、炭化层强度(W)、炭化层结构密度(ρ)的6个指标评价综合防火性能,进行多指标正交实验分析。最终研究表明,当m(MF-APP)∶m(PEPA)∶m(MEL)=21∶14∶22时,涂料的综合防火性能最佳:8 min以内能完全膨胀出强度高、孔隙密度低的炭质层,模拟大板燃烧30 min后,钢板背温控制在294℃。

Orthogonal experiment design and multi-index range analysis were used to define the optimum ratio of an intumescent system in flame-retardant coatings： melamine-coated ammonium polyphosphate（MF-APP）/pentaerythritol phosphate（PEPA）/melamine（MEL） system. To begin with, the orthogonal experiment was used to design the formulations of the flame-retardant coatings. Then, through the big panel burning simulation test, six experimental indexes including the initial temperature of the steel back temperature platform（T1）, the time needed for steel back temperature to reach the platform（t）, the steel back temperature after 30 min（T2）, the expansion rate（H）, the charring layer＇s strength（W） and the charring layer structure＇s density（ρ） were gained to evaluate the coatings＇ flame-retardant performance. Multi-index range analysis was applied. Results show that the optimum ratio is m（MF-APP）∶m（PEPA）∶m（MEL）=21∶14∶22, with which the coatings have the best flame-retardant performance： the coatings fully expanded into a porous char with high strength in around 8 min. The steel back temperature was controlled under 294 ℃ after 30 min of big panel burning simulation.