低甲醛脲醛树脂基钢结构防火涂料的制备

Preparation of Fire Retardant Coating for Steel Structure by Low Formaldehyde Urea-Formaldehyde Resin

本试验制备了一种低甲醛脲醛树脂基膨胀型钢结构防火涂料,探究了脲醛树脂加入量对防火涂料性能的影响,并分析其耐火机理。结果表明,在甲醛与尿素低摩尔比(0.8∶1)时,加入0.1%过氧化氢,制备低甲醛脲醛树脂,甲醛含量符合GB 18582-2020规定;加入脲醛树脂对膨胀型钢结构防火涂料的基本性能无影响,对涂层发泡性能和耐火性能影响显著,当脲醛树脂加入量在6%~10%时,涂层发泡厚度在3 cm以上,钢板背面温度在300℃以下,最低为271.9℃;脲醛树脂发生热解,分子链断裂产生大量阻燃气体,形成致密碳层,起到气源、碳源的作用。

In this paper,a low formaldehyde urea-formaldehyde resin-based intumescent fire retardant coating for steel structure was prepared.The effect of urea-formaldehyde resin content on the performance of fire retardant coating was investigated,and the fire resistance mechanism was analyzed.The results showed that the low formaldehyde urea-formaldehyde resin was prepared by adding 0.1%hydrogen peroxide at the low molar ratio of formaldehyde to urea(0.8∶1),and the formaldehyde content met the requirements of GB 18582-2020.The addition of urea-formaldehyde resin has no effect on the basic properties of the intumescent fire retardant coating for steel structure,but has a significant effect on the foaming performance and fire resistance of the coating.When the addition amount is 6%-10%,the foaming thickness of the coating is more than 3 cm,and the temperature of the back surface of the steel plate is below 300℃,the lowest is 271.9℃.In addition,pyrolysis of urea-formaldehyde resin occurs,and the molecular chain breaks to produce a large amount of flame retardant gas,forming a dense carbon layer,which plays the role of gas source and carbon source.