Melamineureaformaldehyde

Melamine-urea-formaldehyde (MUF) resins are thermosetting amino resins produced by the condensation of formaldehyde with melamine and urea. They form crosslinked networks on heating and are used as binders and adhesives in wood composites and laminates.

In production, formaldehyde reacts with the amino groups of melamine and urea under alkaline conditions to form methylol derivatives, which then condense to a rigid network upon curing. The melamine content improves hydrolytic and moisture resistance relative to urea-formaldehyde (UF) resins, while the urea component lowers cost and allows processing at lower temperatures than MF resins. Typical MUF formulations balance melamine, urea, and formaldehyde to achieve desired cure speed, bond strength, and water resistance. MUF resins cure at moderate temperatures and pressures and yield hard, thermoset bonds with good heat and moisture stability. They can emit formaldehyde, though emissions are often lower than UF for the same total formaldehyde content and are regulated in many jurisdictions.

Applications include the primary use as an adhesive for wood-based panels such as plywood, particleboard, and medium-density fiberboard, and for bonding veneers and decorative laminates (high-pressure laminates). MUF is preferred when moisture resistance and bond durability are important compared with UF, and when cost and cure conditions are balanced against MF.

Variants and performance: The melamine/urea ratio influences water resistance, cure speed, and brittleness. MUF resins are available in low- and ultra-low formaldehyde emission grades to meet environmental requirements.