Formaldehyde is produced by dehydrogenation or oxidation of methanol catalyzed by silver, copper and other metals. It can also be separated from the oxidation products of hydrocarbons to produce formaldehyde. It can be used as raw materials for phenolic resin, urea formaldehyde resin, vinylon, urotropine, pentaerythritol, dyes, pesticides and disinfectants. At the same time, it is a colorless gas, but it is irritating to human eyes and nose.
The main sources of formaldehyde are: building materials, interior decoration materials and daily necessities. Formaldehyde mainly exists in plates, adhesives and other materials.
Formaldehyde is an organic chemical substance. The chemical formula is HCHO or CH З o, with a molecular weight of 30.03, also known as formic aldehyde. It is a colorless and irritant gas, which can stimulate human eyes and nose. The relative density of gas is 1.067 (air = 1), and the density of liquid is 0.815g/cm ³ （-20℃）。 Melting point - 92 ℃, boiling point - 19.5 ℃. Soluble in water and ethanol. The concentration of aqueous solution can reach up to 55%, generally 35% - 40%, usually 37%, which is called formaldehyde water, commonly known as formalin.
Common formaldehyde sources:
1. Plywood, fiberboard, particleboard and other man-made boards contain glue and adhesive. The glue used to paste ceramic tiles also contains formaldehyde.
2. Furniture made of wood-based panels. The adhesives used in the production of wood-based panels are mainly composed of formaldehyde. The residual and non reactive formaldehyde in the panel will gradually release to the surrounding environment, which is the main body of formaldehyde in the indoor air.
3. Other decorative materials that contain formaldehyde and may be distributed to the outside world, such as wall cloth, wallpaper, chemical fiber carpet, paint and coating, etc.