Rapid Preparation of Flame-Retardant Coatings Using Polyurethane Emulsion Mixed with Inorganic Fillers

The traditional aqueous flame-retardant coating faces the problem of slow solvent evaporation rate in the preparation process. It is an urgent problem to ensure that the function of the membrane is not destroyed while accelerating the solvent volatilization. Herein, we fabricated films on the metal substrate surface by a totally novel method: demulsification-induced fast solidification to rapidly obtain the flame-retardant coating. The environmentally friendly flame retardants aluminum hydroxide and red phosphorus were mixed with the commercial water-based polyurethane 906 emulsion to explore the optimal mixing ratio, where the adhesion of the flame-retardant reached the Grade 3 standard, the sample remained intact after the 100 cm drop hammer test and the limiting oxygen index value reached 30.4%. In addition, compared with the traditional process, this method, with the advantages of rapidly drying, environmentally friendly, uniformly prepared coatings on the surface of any shape substrates, as well as accurate and controllable coating thickness, can be widely applied in the flame-retardant field.