Melamine resin

Melamine resinormelamine formaldehyde(also shortened tomelamine) is a resin withmelaminerings terminated with multiple hydroxyl groups derived from formaldehyde. Thisthermosetting plasticmaterial is made from melamine andformaldehyde.In its butylated form, it is dissolved inn-butanolandxylene.It is then used to cross-link withalkyd,epoxy,acrylic,andpolyesterresins, used in surface coatings. There are many types, varying from very slow to very fast curing.

Idealized subunit of a melamine-formaldehyde resin (R - H, alkyl)

Curing

Melamine-formaldehyde can becuredby heating, which induces dehydration and crosslinking. The crosslinking can be carried out to a limited degree to give resins. Either the melamine-formaldehyde resins or melamine-formaldehyde "monomer" can be cured by treatment with any of severalpolyols.

Applications

Construction material

The principal use of melamine resin is as the main constituent of high-pressurelaminates,such asFormicaandArborite,and oflaminate flooring.Melamine-resin tile wall panels can also be used aswhiteboards.Melamine formaldehyde is used in plastic laminate and overlay materials. Formaldehyde is more tightly bound in melamine-formaldehyde than it is in urea-formaldehyde, reducing emissions.

Other

In the kitchen

A melamine-resin plate

A melamine-resinladle

Melamine resin is often used in kitchen utensils and plates (such as Melmac). Because of its highdielectric constantranging from 7.2 to 8.4, melamine resin utensils and bowls are notmicrowave safe.

During the late 1950s and 1960s melaminetablewarebecame fashionable. Aided by the stylish modern designs ofA. H. Woodfulland the Product Design Unit of British Industrial Plastics, it was thought to threaten the dominant position ofceramicsin the market. In the late 1960s the tendency of melamine cups and plates to become stained and scratched led to a decline in sales, and eventually the material became largely restricted to thecampingandnurserymarkets, in which its light weight and resistance to breaking were valued.

Cabinet and furniture making

Melamine resin is often used to saturate decorative paper that is laminated under heat and pressure and then pasted ontoparticle board;the resulting panel, often calledmelamine,is commonly used inready-to-assemble furnitureandkitchen cabinets.

Melamine is available in diverse sizes and thicknesses, as well as a large number of colors and patterns. The sheets are heavy for their size, and the resin is prone to chipping when being cut with conventional table saws.

Carbon capture

Melamine, with the addition of formaldehyde,cyanuric acid,and DETA (diethylenetriamine) has been demonstrated to bind CO₂for purposes ofcarbon capture,according to researchers atStanford,Berkeley,andTexas A&M.

Microencapsulation of active compounds

Melamine-based resin (e.g., melamine-formaldehyde or melamine-urea-formaldehyde resins) can also be used to microencapsulate active agents, such as healing agents orphase change materials,to prevent leakage above their melting temperature.The resulting surface is quite inert and can hardly be modified with traditional techniques such assilanization.Some research has shown thatpolydopaminecan be effective as a surface modifier for this resin.

Production and structure

Melamine-formaldehyde resin forms via thecondensationofformaldehydewith melamine to give, under idealized conditions, the hexa-hydroxymethyl derivative. Upon heating in the presence of acid, this or similar hydroxymethylated species undergoes further condensation and crosslinking. Linkages between the heterocycles include mono-, di-, and polyethers.The microstructure of the material can be analyzed by NMR spectroscopy.The crosslinking density of melamine resins can be controlled by co-condensation with bifunctional analogues of melamine,benzoguanamineandacetoguanamine.

Idealized chemical reactions leading to melamine-formaldehyde resin (Melmac)

See also

• Melamine foamis a special form of melamine resin. It is used mainly as an insulating and soundproofing material and more recently as a cleaning abrasive.
• Formicais a brand of composite materials manufactured by the Formica Corporation. In common use, the term refers to the company's classic product, a heat-resistant, wipe-clean, plastic laminate of paper or fabric with melamine resin.