Urea buttons, also known as urea-formaldehyde resin buttons, urea and formaldehyde reaction of the polymer. Also known as urea-formaldehyde resin. English abbreviation UF. Crosslinking occurs during processing and forming, and the product is an insoluble thermosetting resin. The cured urea-formaldehyde resin is lighter in color than phenolic resin, translucent, resistant to weak acid and weak base, good in insulation and wear resistance. Welcome to customize 2 hole buttons here.