urea-formaldehyde foam
Sprayed insulation consisting of urea-formaldehyde, a yellowish synthetic resin.
Urea-formaldehyde foam insulation is a kind of thermal insulation sprayed from a gun which mixes urea-formaldehyde resin with foaming agents. The chemical is synthetic, and forms a brittle yellowish or butterscotch-colored resin when it is cured. Initial setting and full curing occur on different timescales; full curing can take several weeks.
This material can emit formaldehyde into the air, creating potential health concerns. It is costly to remove, and in most areas has not been widely used as an insulation material since the 1970s.
The material is foamed in place from urea-formaldehyde resin. Formaldehyde emissions depend on the product and its condition, including age, temperature, and humidity; this resin is distinct from polyurethane.