Fireproof coatings are one of the varieties of special coatings and are an important part of fireproof building materials. Fireproof coatings are generally used on the surface of steel structure substrates, which can reduce the flammability of steel surfaces and stop the rapid spread of fire, so as to improve the fire resistance limit of steel. Coating fireproof coatings with excellent performance on the surface of substrates can not only play a decorative role, but also prevent corrosion, rust, acid and alkali resistance, smoke prevention, etc. More importantly, when a fire occurs, fireproof coatings can prevent the spread of flames, control the development of fire, and effectively protect the internal structure. Magnesium hydroxide, as a representative of inorganic flame retardant, plays an increasingly important role in fireproof materials due to its many advantages such as good thermal stability, no volatilization, no precipitation, no toxic gases, and no pollution.
Flame retardant system materials are the core of fire retardant coatings, and their properties have a great impact on the performance of fire retardants. There are two types of flame retardants: inorganic and organic. Inorganic flame retardants are mainly additive types, including antimony-based flame retardants, aluminum hydroxide, magnesium hydroxide flame retardants, phosphorus-containing inorganic flame retardants, boron-containing and molybdenum-containing flame retardants and smoke suppressants. They have the characteristics of thermal stability, low toxicity, no corrosive gas, and long-lasting flame retardant effect. However, due to their large filling amount in the polymer, coupled with the influence of their inherent characteristics, the processing formability, mechanical properties, and electrical properties of the polymer will be reduced.
Magnesium hydroxide, as the most popular environmentally friendly flame retardant at present, has a good flame retardant effect when added to fireproof coatings, and has the characteristics of fire resistance limit, high adhesion, good water resistance, and no toxic gases. At present, the amount of magnesium hydroxide flame retardant is increasing at an annual rate of 20%, which has broad market prospects. On the other hand, due to the characteristics of nanomaterials such as small size effect, surface and interface effect, quantum size effect and macroscopic quantum tunneling effect, as well as the advantages of low filling amount and high flame retardant efficiency. According to the above characteristics, the surface of magnesium hydroxide can be modified to nano-magnesium hydroxide, and the effect of nano-magnesium hydroxide as a flame retardant for fire retardant coatings will be better.