Fire retardant coatings are divided into three types: thick coating type, thin coating type and ultra-thin type according to the coating film thickness. In addition to the relatively large influence of flame retardants and emulsions on the performance of fire retardant coatings, the influence of fillers is also very important. Although the proportion of fillers in the entire fire retardant coating is not large, it has an important impact on the performance of the fire retardant coating. In ordinary coatings, fillers usually play the role of reducing costs and improving the physical and chemical properties of coatings, while in fire-retardant coatings, they also play a role of flame retardant. Due to the differences in the composition, morphology, physical properties, etc. of each filler, the roles played in the fire retardant coatings are also different.

1. Although the coating with added calcium carbonate has a high expansion height and increases the distance between the flame and the steel plate, due to the large bubble in the middle instead of a uniform and dense honeycomb carbon layer, the heat insulation effect is not good, and the fire resistance time is short. Therefore, calcium carbonate is not suitable for use in fire retardant coatings.

2. Although the expansion height of the talc powder carbon layer is lower than that of calcium carbonate, the quality of the talc powder carbon layer is better than that of calcium carbonate, and the refractory time of the coating containing talc powder is better than that of calcium carbonate, indicating that the quality of the carbon layer is better than the expansion height. more important.

3. Comparing kaolin, talc and wollastonite powder with the same quality of carbon layer, wollastonite powder has the highest swelling height, followed by kaolin, and talc powder is the lowest. The order of refractory time is also wollastonite powder > kaolin clay > talc powder. It can be seen from this that the order of the fire resistance time is the same as the order of the expansion height, which means that when the quality of the carbon layer reaches the standard (that is, the middle of the carbon layer is dense honeycomb), the higher the expansion height, The effect of fire and heat insulation is better. That is to say, the effect of kaolin and talc is the same as that of wollastonite powder, but the performance is not as good as that of wollastonite powder. Of course, the carbon layer should not be too high, otherwise, the carbon layer will be separated from the steel plate, and it will not play a role in fire prevention.

4. Use wollastonite powder, aluminum hydroxide and hollow microbeads as fillers for the fireproof coating, in which wollastonite powder plays the role of skeleton, aluminum hydroxide plays the role of smoke suppression and cooling, and hollow microspheres play the role of enhancing the strength of the carbon layer.

In a word, by taking full advantage of the low price of fillers and cooperating with other flame retardant additives, fire retardant coatings with excellent performance can be prepared.