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Urea formaldehyde (UF) is a cheap and scratch-resistant resin used in pressed wood products. UF hydrolyzes in humid conditions, increasing formaldehyde levels in indoor air, which can cause health problems. Formaldehyde analysis can be performed to reduce exposure. Phenol-formaldehyde (PF) resins reduce formaldehyde emissions.
Urea formaldehyde (UF) is an economical thermosetting resin widely used in the wood products industry. These resins cure easily and are scratch resistant. They are mainly used in the production of pressed wood products.
In the laboratory, urea formaldehyde resins are prepared by treating urea with formaldehyde in an alkaline or neutral medium to produce dimethylol urea, which then undergoes polycondensation, a chemical process that results in a polymer, when heated in an acidic medium. This resin is mainly used as an adhesive in the medium density fibreboard (MDF) industry because it can be produced at very low cost from readily available raw materials. MDF is used for making furniture, floor panels, interior building materials, and more.
The major disadvantage of this resin is that it hydrolyzes, or decomposes, in extremely humid conditions and at high temperatures, which limits its use as an outdoor building material. Also, when pressed wood products made with it are used indoors, there is a dramatic increase in the levels of formaldehyde in the indoor air. The increased use of pressed wood products, such as fiberboard, particle board, and hardwood plywood panels, in a limited space can be considered a significant reason for the deterioration of indoor air quality (IAQ) .
Formaldehyde emissions above a certain level, higher than 0.1 parts per million, can have toxic effects on humans. It can cause breathing difficulties, dizziness, skin irritation and nausea. An increase in formaldehyde levels in the air can also trigger asthma attacks in asthmatic patients. Some people are also allergic to formaldehyde, which is a confirmed carcinogen.
In the past, urea formaldehyde foam insulation (UFFI) was installed in the wall voids of houses for energy saving purposes. Eventually, possible health risks from formaldehyde emissions lead to its ban in most countries by 1980. Old houses, especially those built in the 1970s, often still have UFFI installed, but the amount of formaldehyde emissions in these homes is considerably lower than that in new homes. This is mainly due to an increase in the use of pressed wood products in cabinets, furniture and other interior building materials.
Formaldehyde analysis can be performed in specific laboratories by sampling the indoor air. Indoor formaldehyde test kits are also available. The use of pressed wood products containing phenol-formaldehyde (PF) resins, also known as “exterior grade” pressed wood products, significantly reduces the emission of formaldehyde. Furthermore, formaldehyde levels in indoor air can be reduced by using air conditioners and dehumidifiers and by providing sufficient ventilation to the rooms.
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