The main function of fire-resistant coatings on steel structures is to prevent fire. The anti-rust of steel structures still needs to be completed by anti-rust primers. The anti-rust primers used for fire-resistant coatings for steel structures need to be compatible with fire-resistant coatings. Has very good adhesion. On the basis of the primer , carry out the construction of the fireproof coating, and apply the corresponding thickness according to the requirements of the fire resistance limit. The antirust primers used for the lower layer of fireproof coatings mainly include alkyd zinc phosphate antirust primers, epoxy zinc phosphate antirust primers, epoxy zinc-rich primers and inorganic zinc silicate primers. The surface of zinc-rich primers should be sealed with epoxy mica iron, so as to avoid the production of zinc salts during the production of steel structures and affect the compatibility with fire-resistant coatings.
In the fire protection coating system, the sealing top coat is very important. Since the decorative properties of the fire retardant coating itself are relatively poor, it is very necessary to apply a top coat. Theoretically speaking, organic matter will age and degrade, which is fatal to the performance of fire retardant coatings. If it is coated with an anti-aging topcoat, this problem can be basically solved.
The finish paint on the surface layer of fire retardant coating, one is to resist the damage of corrosive medium and external stress to the fire retardant coating, and can effectively seal and block moisture and moisture from penetrating into the surface of the coating, so as to cooperate with the top and bottom of the fire retardant coating to play a protective role. The overall effect of steel; the second is to decorate and beautify the building as a whole, such as good luster, rich colors, flat and smooth appearance, etc. The top coats of fire retardant coatings mainly include the following categories: alkyd top coats, acrylic top coats, polyurethane paints, silicone paints, epoxy paints, etc. Theoretically speaking, thermoplastic acrylic topcoat is a more suitable product, while two-component polymeric topcoat may affect the performance of fire retardant coating to a certain extent.
The primer and topcoat system of fireproof coatings for steel structures are shown in Figure 3-4.
