Problem

Formaldehyde was developed back in 1859, but the increased use of this substance in production was started only in the early 20th century, along with the development and implementation of other polymer materials in production. In 2010, in Europe alone, 3.6 million t of formaldehyde were produced for the needs of different sectors. The most popular binder for wood-based panels is urea-formaldehyde and phenol-formaldehyde resins. The most significant disadvantage of formaldehyde resins is the harmful effect on human health. Wood-based panels with formaldehyde are toxic to humans both in the process of their manufacture and when expluatating finished products, since over time, the release of carcinogenic formaldehyde emissions occurs. If the concentration of formaldehyde in the air exceeds 0.1 ppm, it irritates the eyes, throat and nasal mucosa, and makes breathing difficult. The World Health Organization (WHO) International Agency for Cancer Research (IARC) has recognized formaldehyde as a carcinogenic substance for humans.

Discussion

In Germany, already since 1977, the annual maximum permissible norm of formaldehyde in residential rooms is 0.1 ppm, while the norm established by the WHO is 100 µg/m3. Aware of the seriousness of the problem, on July 7, 2010, US President Barack Obama signed a law on the formaldehyde standard in wood-based panel products, which came into force on 1 January, 2013. Formaldehyde release has been established to not exceed 0.09 ppm. In Canada, the law provides that in rooms where temporarily staying, the permissible concentration of formaldehyde is 123 µg/m3, and in residential rooms – 50 µg/m3. Unfortunately, sometimes it is found that, in residential rooms with new furniture, the concentration of formaldehyde exceeds 0.3 ppm; therefore, in the European Union, the norm of formaldehyde in wood-based panels is 0.2%, but all products containing more than 0.05% of formaldehyde, must be accompanied by a warning. Especially intensively formaldehyde is released by urea-formaldehyde resins. Reducing the release of formaldehyde from the binder, additives, for example, the addition of boric acid and calcium metasilicate solves the problem only partially (by 15-30%). Slightly better results have been achieved at the Fraunhofer Institute for Wood Science in Germany by introducing modified zeolites (by 40-70%) into the composition of wood-based panels. The release is also reduced by the use of NH4Cl as a hardener (up to 20%).