Urea-formaldehyde

A non-transparent thermosetting resin or plastic

Urea-formaldehyde (UF) is a non-transparent thermosetting resin or plastic, made from urea and formaldehyde heated in the presence of a mild alkali such as ammonia or pyridine.

History

Urea-formaldehyde was first synthesized in the early 20th century. It gained popularity in the 1930s and 1940s as a material for molding and adhesive applications. Its use expanded rapidly due to its low cost and ease of production.

Properties

Urea-formaldehyde resins are known for their high tensile strength, flexural modulus, and heat distortion temperature. They are also characterized by their hardness, low water absorption, and high surface hardness. However, they are brittle and can degrade under prolonged exposure to moisture.

Applications

Urea-formaldehyde is widely used in the production of particle board, plywood, and medium-density fibreboard (MDF) due to its adhesive properties. It is also used in textile finishing, paper processing, and as a foam insulation material.

Molding

UF resins are used in the production of molded products such as electrical fittings, knobs, and handles. The material's ability to be easily colored and its high surface hardness make it suitable for these applications.

Adhesives

Urea-formaldehyde adhesives are used in the wood industry for bonding wood products. They provide strong bonds and are cost-effective, although they can release formaldehyde over time, which has raised health concerns.

Insulation

Urea-formaldehyde foam insulation (UFFI) was popular in the 1970s and 1980s for insulating homes. However, its use has declined due to concerns about formaldehyde emissions.

Health and Safety

Exposure to formaldehyde, a component of urea-formaldehyde, can cause irritation of the eyes, nose, and throat, and has been classified as a carcinogen. Regulations have been implemented to limit formaldehyde emissions from UF products.

Environmental Impact

The production and disposal of urea-formaldehyde can have environmental impacts due to the release of formaldehyde. Efforts are being made to develop low-emission UF resins and to find alternative materials.

Gallery

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  Chemical structure of urea-formaldehyde resin

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  A selection of urea-formaldehyde objects at the Science Museum

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  Urea-formaldehyde foam insulation

Related pages

• Formaldehyde
• Thermosetting polymer
• Adhesive

References

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  Urea-formaldehyde resin synthesis diagram

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  A selection of urea-formaldehyde objects at the Science Museum

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  Urea-formaldehyde insulation