Ureaformaldehydeharsen

Ureaformaldehydeharsen, commonly called urea‑formaldehyde resin (UF), denotes a family of thermosetting polymers produced by the condensation of urea with formaldehyde. These aminoplast resins form through the initial formation of methylol urea derivatives, which then crosslink to an insoluble network upon curing. The resin composition can vary in the urea-to-formaldehyde ratio and methylol content, allowing adjustments in cure speed, bond strength, and moisture resistance.

UF resins are widely used as wood adhesives because of their strong bonding to cellulose-containing substrates, low cost, and good heat resistance after cure. They are employed in particleboard, medium-density fibreboard (MDF), plywood, and other wood-based panels, as well as molding compounds and laminates.

A notable characteristic of UF resins is their formaldehyde emission potential. Formaldehyde can be released during curing and, in some products, for extended periods during use, raising health and indoor air quality concerns. Consequently, regulatory limits and voluntary industrial standards have driven the development of low-emission formulations and of alternative resins such as melamine-urea-formaldehyde and phenol-formaldehyde systems.

UF resins cure by polymerization and crosslinking, typically initiated thermally or with catalysts. They tend to be relatively brittle and moisture-sensitive compared with some other resins, making formulation adjustments or moisture barriers important in many applications.

See also: melamine-formaldehyde resin, phenol-formaldehyde resin.