Wikipedia
Urea-formaldehyde
Urea-formaldehyde, also known as urea-methanal, so named for its common synthesis pathway and overall structure, is a non-transparent thermosetting resin or plastic, made from urea and formaldehyde heated in the presence of a base. These resins are used in adhesives, finishes, particle board, MDF, and molded objects. UF and related amino resins are considered a class of thermosetting resins of which urea-formaldehyde resins make up 80% produced globally. Examples of amino resins use include in automobile tires to improve the bonding of rubber to tire cord, in paper for improving tear strength, in molding electrical devices, jar caps, etc.