What is Amino Resins?
Amino resins are thermosetting polymers. The most common types of amino resins are urea-formaldehyde (UF) and melamine-formaldehyde (MF). This resins are characterized by being clearer and harder (tensile strength) than phenolics. However, their breakability and heat resistance are lower. Melamine resin has better heat and moisture resistance and better hardness than its urea analogues. This resin is widely used in various industries such as wood adhesives, plastic bottle materials, to mica film raw materials.
Urea-formaldehyde is formed from the reaction of formaldehyde (HCHO) with compounds containing amino (NH2) and then reacted with alcohol (R-OH). Formaldehyde is a pungent gas, but it dissolves in water to form the substance we know as Formalin. It is also available in solid form, paraformaldehyde, which is a polymerized form. While urea is a white crystalline solid with a melting point of 133° C dissolved in water, and is made by the high pressure reaction of carbon dioxide and ammonia.
Melamine-formaldehyde (MF) resin is formed from melamine and Formaldehyde. Melamine is a triamino and triazine which is a white crystalline solid with a melting point of 350° C. It is insoluble in water. MF resins have many advantages over UF resins. MF adhesives are also less prone to damage than UF adhesives, and thus do not cause formaldehyde gas release problems. Unfortunately, their prices are way above UF prices. In surface coatings, MF resins are more widely used than UF resins as curing agents for acrylic, polyester, and other resins. Because they provide coatings with superior properties for applications in cars, appliances, and other high-value durable goods.
Source
- https://chempedia.info/info/amino_resins/
- https://ihsmarkit.com/products/amino-resins-chemical-economics-handbook.html
- Oil and Colour Chemists’ Association, Australia