HDI is one of a group of compounds known as aliphatic diisocyanates. At room temperature, HDI is a colourless liquid with a sharp pungent odour and low volatility.
Hazardous properties
Like most diisocyanates, exposure to HDI either by inhalation, ingestion or skin contact can lead to sensitisation(1). It is irritating to the skin (causing dermatitis) and eyes and can affect the respiratory system causing dyspnoea (breathing difficulty), pulmonary oedema and asthma.
Although it has low volatility, the fact that it is used in spray-on coatings means that it is present as an aerosol and, as such, can be readily inhaled.
Occurrence/Uses
HDI is commonly used as a curing agent in high performance polyurethane coatings for automobile, aircraft and marine applications.
Detectors available
Colorimetric paper tape (0 – 200 ppb)
Suggested alarm level(s)
5 ppb
Notes
(1) Sensitisation is a phenomenon occurring in some individuals, whereby exposure to a substance leads to those individuals having an increased sensitivity to the effects of that substance.
