Melamine resin or melamine formaldehyde (also shortened to melamine) is a resin with melamine rings terminated with multiple hydroxyl groups derived from formaldehyde. This
thermosetting plastic
In materials science, a thermosetting polymer, often called a thermoset, is a polymer that is obtained by irreversibly hardening (" curing") a soft solid or viscous liquid prepolymer (resin). Curing is induced by heat or suitable radiation and ...
material is made from
melamine
Melamine is an organic compound with the formula C3H6N6. This white solid is a trimer of cyanamide, with a 1,3,5-triazine skeleton. Like cyanamide, it contains 67% nitrogen by mass, and its derivatives have fire retardant properties due t ...
and
formaldehyde
Formaldehyde ( , ) (systematic name methanal) is a naturally occurring organic compound with the formula and structure . The pure compound is a pungent, colourless gas that polymerises spontaneously into paraformaldehyde (refer to section F ...
.
[ In its butylated form, it is dissolved in ''n''-butanol and ]xylene
In organic chemistry, xylene or xylol (; IUPAC name: dimethylbenzene) are any of three organic compounds with the formula . They are derived from the substitution of two hydrogen atoms with methyl groups in a benzene ring; which hydrogens are s ...
. It is then used to cross-link with alkyd
An alkyd is a polyester resin modified by the addition of fatty acids and other components. Alkyds are derived from polyols and organic acids including dicarboxylic acids or carboxylic acid anhydride and triglyceride oils. The term ''alkyd'' is a m ...
, epoxy
Epoxy is the family of basic components or cured end products of epoxy resins. Epoxy resins, also known as polyepoxides, are a class of reactive prepolymers and polymers which contain epoxide groups. The epoxide functional group is also coll ...
, acrylic
Acrylic may refer to:
Chemicals and materials
* Acrylic acid, the simplest acrylic compound
* Acrylate polymer, a group of polymers (plastics) noted for transparency and elasticity
* Acrylic resin, a group of related thermoplastic or thermosett ...
, and polyester
Polyester is a category of polymers that contain the ester functional group in every repeat unit of their main chain. As a specific material, it most commonly refers to a type called polyethylene terephthalate (PET). Polyesters include natural ...
resins, used in surface coatings. There are many types, varying from very slow to very fast curing.
Curing
Melamine-formaldehyde can be cured by 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 several polyol
In organic chemistry, a polyol is an organic compound containing multiple hydroxyl groups (). The term "polyol" can have slightly different meanings depending on whether it is used in food science or polymer chemistry. Polyols containing two, thr ...
s.
Applications
Construction material
The principal use of melamine resin is as the main constituent of high-pressure laminates, such as Formica
''Formica'' is a genus of ants of the family Formicidae, commonly known as wood ants, mound ants, thatching ants, and field ants. ''Formica'' is the type genus of the Formicidae, and of the subfamily Formicinae. The type species of genus ''For ...
and Arborite
Arborite is the leading Canadian manufacturer of high-pressure decorative plastic laminates (HPL). Best known as a counter top surfacing material, laminate is a durable decorative veneer applied to cabinetry, furniture, and other horizontal and ...
, and of laminate flooring
Laminate flooring (also called floating wood tile in the United States) is a multi-layer synthetic flooring product fused together with a lamination process. Laminate flooring simulates wood (or sometimes stone) with a photographic applique la ...
. Melamine-resin tile wall panels can also be used as whiteboard
A whiteboard (also known by the terms marker board, dry-erase board, dry-wipe board, and pen-board) is a glossy, usually white surface for making non-permanent markings. Whiteboards are analogous to blackboards, but with a smoother surface all ...
s. 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
Melamine resin is often used in kitchen utensils and plates (such as Melmac). Melamine resin utensils and bowls are not microwave safe.
During the late 1950s and 1960s melamine tableware
Tableware is any dish or dishware used for setting a table, serving food, and dining. It includes cutlery, glassware, serving dishes, and other items for practical as well as decorative purposes. The quality, nature, variety and number of o ...
became fashionable. Aided by the stylish modern designs of A. H. Woodfull and the Product Design Unit of British Industrial Plastics, it was thought to threaten the dominant position of ceramic
A ceramic is any of the various hard, brittle, heat-resistant and corrosion-resistant materials made by shaping and then firing an inorganic, nonmetallic material, such as clay, at a high temperature. Common examples are earthenware, porcelain ...
s in 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 the camping
Camping is an outdoor activity involving overnight stays away from home, either without shelter or using basic shelter such as a tent, or a recreational vehicle. Typically, participants leave developed areas to spend time outdoors in more nat ...
and nursery markets, 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 onto particle board
Particle board, also known as chipboard or low-density fiberboard, is an engineered wood product manufactured from wood chips and a synthetic resin or other suitable binder, which is pressed and extruded. Particle board is often confused with ...
; the resulting panel, often called ''melamine'', is commonly used in ready-to-assemble furniture
Ready-to-assemble furniture (RTA), also known as knock-down furniture (KD), flat pack furniture, or kit furniture, is a form of furniture that requires customer assembly. The separate components are packed for sale in cartons which also contain ...
and kitchen cabinet
Kitchen cabinets are the built-in furniture installed in many kitchens for storage of food, cooking equipment, and often silverware and dishes for table service. Appliances such as refrigerators, dishwashers, and ovens are often integrated ...
s.
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
Cyanuric acid or 1,3,5-triazine-2,4,6-triol is a chemical compound with the formula (CNOH)3. Like many industrially useful chemicals, this triazine has many synonyms. This white, odorless solid finds use as a precursor or a component of bleach ...
, and DETA (diethylenetriamine
Diethylenetriamine (abbreviated and also known as 2,2’-Iminodi(ethylamine)) is an organic compound with the formula HN(CH2CH2NH2)2. This colourless hygroscopic liquid is soluble in water and polar organic solvents, but not simple hydrocarbons. ...
) has been demonstrated to bind CO2 for purposes of carbon capture Carbon capture may refer to:
* Carbon capture and utilization, where the captured carbon dioxide is used
* Carbon sequestration, where the captured carbon dioxide is stored
** Carbon capture and storage, referring to carbon sequestration from point ...
, according to researchers at Stanford
Stanford University, officially Leland Stanford Junior University, is a private research university in Stanford, California. The campus occupies , among the largest in the United States, and enrolls over 17,000 students. Stanford is considere ...
and Berkeley
Berkeley most often refers to:
*Berkeley, California, a city in the United States
**University of California, Berkeley, a public university in Berkeley, California
* George Berkeley (1685–1753), Anglo-Irish philosopher
Berkeley may also refer ...
.
Production and structure
Melamine-formaldehyde resin forms via the condensation
Condensation is the change of the state of matter from the gas phase into the liquid phase, and is the reverse of vaporization. The word most often refers to the water cycle. It can also be defined as the change in the state of water vapor to ...
of formaldehyde
Formaldehyde ( , ) (systematic name methanal) is a naturally occurring organic compound with the formula and structure . The pure compound is a pungent, colourless gas that polymerises spontaneously into paraformaldehyde (refer to section F ...
with 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 polyether
In organic chemistry, ethers are a class of compounds that contain an ether group—an oxygen atom connected to two alkyl or aryl groups. They have the general formula , where R and R′ represent the alkyl or aryl groups. Ethers can again be c ...
s. The microstructure of the material can be analyzed by NMR spectroscopy.[David R. Bauer "Melamine/formaldehyde crosslinkers: characterization, network formation and crosslink degradation" Progress in Organic Coatings 1986, Volume 14, pp. 193–218. ] The crosslinking density of melamine resins can be controlled by co-condensation with bifunctional analogues of melamine, benzoguanamine
Benzoguanamine is an organic compound with the chemical formula (CNH2)2(CC6H5)N3. It is related to melamine but with one amino group replaced by phenyl. Benzoguanamine is used in the manufacturing of melamine resins. Unlike melamine ((CNH2)3N3 ...
and acetoguanamine.
See also
* Melamine foam
A " Mr. Clean Magic Eraser" brand sponge, made from melamine foam
Melamine foam is a foam-like material consisting of a melamine-formaldehyde condensate. It is the active component of a number of abrasive cleaner sponges, notably the Magic Era ...
is a special form of melamine resin. It is used mainly as an insulating and soundproofing material and more recently as a cleaning abrasive.
* Formica
''Formica'' is a genus of ants of the family Formicidae, commonly known as wood ants, mound ants, thatching ants, and field ants. ''Formica'' is the type genus of the Formicidae, and of the subfamily Formicinae. The type species of genus ''For ...
is 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.
References
{{Authority control
Kitchenware
Building materials
Organic polymers
Thermosetting plastics