流变助剂对膨胀型钢结构防火涂料性能的影响

Influence of Rheological Additives on the Performance of Intumescent Fire Retardant Coatings for Steel Structure

以溶剂型丙烯酸树脂及氯化石蜡为基料,多聚磷酸铵、季戊四醇和三聚氰胺为膨胀体系,通过不同温度下炭层质量保持率、炭层强度、膨胀倍数、炭层形貌、耐火时间等考察了不同类型的流变助剂对防火涂料性能的影响。结果表明:流变助剂对膨胀型钢结构防火涂料性能的影响非常大。聚酰胺蜡、水合硅酸镁类流变助剂对体系的炭层强度、膨胀倍数、耐火性能等基本无影响;改性水合硅酸镁可以提高防火涂料的耐火时间和炭层强度;亲水气相二氧化硅会导致炭层膨胀倍数和耐火时间增加,同时会降低炭层强度,导致炭层易脱落;疏水二氧化硅、改性蒙脱石类流变助剂会抑制膨胀发泡、提高炭层强度,同时会大幅度降低耐火时间。分析探讨了不同类型流变助剂对防火涂料的性能影响的机理。不同流变助剂在高温膨胀发泡过程中主要影响体系的熔融黏度和膨胀倍数,从而影响防火涂料的综合性能。

Influence of rheological additives on the performance of intumescent fire retardant coatings was investigated by using solvent-based acrylic resin and chlorinated paraffin as binder,APP,PER and MEL as the intumescent system.The influence was analyzed according to char residual mass,fire resistance time,char expansion,char strength and morphology.The results showed that different types of rheological additives had remarkable effect on the performance of intumescent fire retardant coatings.Polyamide wax and hydrated magnesium silicate almost had no impact on the char strength,relative char expansion and fire resistance.Modified hydrated magnesium silicate could improve the char strength and fire resistance time.Hydrophilic fumed silica could increase the relative char expansion and fire resistance time,but at the same time,it could reduce the char strength and cause it to peel off easily.Hydrophobic fumed silica and modified montmorillonite rheology additives could inhibit swelling and foaming and improve the char strength,but at the same time,they would significantly reduce the fire resistance time.Finally,the mechanism of rheological additives on the performance of intumescent fire retardant coatings for steel structure was analyzed.The main mechanism of rheological additives on the performance of intumescent fire retardant coatings was attributed to the impact of the high temperature viscoelastic properties and char expansion.