MDI is liquid under all normal storage standards, with low vapor pressure [40 ℃ vapor pressure < 10-4mmhg], low toxicity in inhalation skin digestion absorption; low volatiles make it less toxic when exposed to touch (such as small amount of leakage, scattering) under normal conditions.
Even so, because MDI is a diphenylmethane gas diisocyanate chemical substance, it still has certain toxicity, which can cause mild to moderate eye irritation mild skin irritation, which can lead to allergy. The higher concentration (TLV) of MDI in air was 0.02ppm.
However, it must be noted that when the temperature of raw materials is heated above 40 ℃ (such as melting) the office environment is well ventilated, its vapor toxicity may be increased. In addition, the selection of the construction site for coating process engineering will cause the concentration of floating particles in the air to rise cause harm. If you work in similar natural environment, you should wear a gas mask a breathing mask. Otherwise, if you inhale the vapor with the concentration exceeding the standard value continuously, it will cause respiratory tract allergy.
Even under all normal standards, due to the cheerful physical properties of MDI, we should be cautious in actual operation.