Plastics

Urea Formaldehyde (UF)

General information

Description

Urea formaldehyde (UF) is a thermoset which feels cold and hard. By nature it is whitish, but was usually coloured, often with a marbled effect. It is not transparent, but can be translucent or opaque. Before 1950 its price was in the midrange, slightly more expensive than PF, but it had nicer colours. Therefore, it was used especially when colour was important for an object. Later UF was replaced by MF which had better properties. Nowadays UF production in relatively small. It is used in adhesives, particle board, and fibre board (MDF).

History

Urea thiourea formaldehyde became available in 1924 and saw a large production until 1935. Meanwhile in 1932 the material was improved to urea formaldehyde (UF) which was very popular between 1932 and 1950 to be replaced ultimately by melamine.

Production, Application, Appearance

Urea thiourea formaldehyde was used widely between 1924 and 1932 as imitation marble, stone and alabaster. From the 1930s onwards it is replaced by UF as a colourful material (often marbled) for the production of household items such as tableware, picnic ware, egg cups, cigarette boxes, electrical fittings and housing and oil bottles.

Properties

Material properties

Thermoset
Density: 1.2-1.31 g/cm3
Melting point: 119°C
Glass transition temperature: °C

Identification properties

Cell structure (foam): not applicable
Smell: no characteristic smell. Can smell of urine occasionally
Touch: feels relatively cold and hard
Sound: Rigid = clear (?)
UV-radiation (when clear): not applicable
Polarizing filters (for clear): not applicable

Degradation

Process

Photo-oxidation, soiling (electrostatic).

Details

UF is not considered a problem plastic.

Symptoms

Discolouration, surface turns matte, fractures in surface, orange-peel skin.

Susceptibility

UV-radiation: Low
Light: Low
Oxygen/Ozone: Low
Temp: Low
RH: High (to low RH)

UF is susceptible to water (vapour and liquid), especially hot water.

Preventive conservation

Recommendations

UV-RADIATION: avoid extremes
LIGHT: 1 slight change in approx. 300 Mlx.h Avoid high light dose
OXYGEN / OZONE: ambient conditions
TEMP: common indoor conditions 10-30°C
RH: keep above 65%