Melamine formaldehyde is a thermosetting plastic (or thermoset) that strengthens as it is heated during its preparation. Once set, it cannot be remolded or set to form a different shape. Melamine formaldehyde plastics retain their strength and shape, unlike other types of thermoplastics that soften with heat and harden when cooled (such as acetate, acrylic and nylon)
MF resins are quite similar to urea-formaldehyde (UF) resins and are fully compatible with them. The resin blend is called melamine-urea-formaldehyde (MUF).
Melamine can also be converted to foam structures with a distinctive pore structure, which is extremely hard. It can be used as an insulating and soundproofing material
- Melamine formaldehyde (MF) resins are primarily made up of melamine and formaldehyde with formaldehyde acting as the cross-linker. The melamine reacts with formaldehyde under slightly alkaline conditions to form mixtures of various methylolmelamines:
- Further heating causes condensation of the methylolmelamines :
- The monomeric form hexamethylolmelamine and the MF resins are very versatile crosslinking agents for a wide variety of polymeric materials both water and solventborne.
- To improve the solubility in solvents, melamine formaldehyde (MF) resins, and the monomeric forms are often etherified with alcohols such as methanol and butanol.
- After acidification, they readily react with thiol, hydroxyl, carboxyl and amide groups to form three-dimensional thermoset polymer networks. The relative reaction rate for these functional groups follows the order of -SH >-OH > -CONH2 > -C00H
The principal use of melamine resin is as the main constituent of high pressure laminates, such as Formica and Arborite, and of laminate flooring. Melamine-resin tile wall panels can also be used as whiteboards.
Melamine resin is often used in kitchen utensils and plates. However, melamine resin utensils and bowls are not microwave safe.
- Cabinet and Furniture Making
Melamine resin is often used to saturate decorative paper that is laminated under heat and pressure and then pasted onto particle board. The resulting panel, often called melamine, is commonly used in ready-to-assemble furniture and kitchen cabinets.
Melamine is or has been used in the manufacture of flame-resistant fibers and textiles. These include upholstery, firemen uniforms, thermal liners, and heat resistant gloves and aprons.
The wooden substrates also contain melamine – plywood, particle boards (PB), medium density fibreboards (MDF) as well as high density fibreboards (HDF), oriented strand boards (OSB) or laminated veneer lumber (LVL) are bonded with melamine containing urea-formaldehyde (UF) adhesives. Melamine adds its unique properties to the product which is, it reduces the release of free formaldehyde and improves the water resistance of the boards.
Specially formulated melamine resin systems are used to produce highly durable coatings. This includes clear finished paper, fabrics, wood and metals. The most popular application is within the automotive industry. MF resins in coating help to reduce solvent emissions and thus have a positive impact on the environment.