Thermal properties of intumescent coating with waterborne melamine-acrylic emulsion resin for plywood

A mixture of etherified melamine–formaldehyde and acrylic emulsion resin was designed, with the hybrid resin improving the fire retardancy of indoor plywood as well as the CO and CO₂ emissions. The water-based hybrid resin exhibited a single curing peak; the need for solvents was reduced. Compared with pure etherified melamine–formaldehyde resin, the hybrid resin had better flame retardancy and produced less pollution. Scanning electron microscopy and cone calorimetry were conducted, and the analyses revealed that lower binder resin concentrations resulted in improved flame retardancy and better char layer formation. When the binder resin concentrations were increased and CO/CO₂ emissions were continued beyond 300 s, the flame retardancy of the intumescent coating was the same as that of the lower binding resin concentrations. Furthermore, the chemical structure and durability of the phosphocarbonaceous structure were verified through Fourier transform infrared spectroscopy and solid-state nuclear magnetic resonance analyses.