DIISOCYANATES

Synonyms

CLASSES

Category

Diisocyanates

Sources/Uses

MDI is used to make rigid foams, while both TDI and MDI are used to make flexible foams, elastomers, and surface coatings. The diisocyanate chemicals, e.g., TDI or MDI, along with various polyols, catalysts, blowing agents, surfactants, and other agents are needed to manufacture urethane polymers. [Klees JE, Ott MG. Diisocyanates in Polyurethane Plastics Applications. Occup Med STAR 14(4):760-2,1999] "Spray-on polyurethane foams and coatings containing isocyanates are applied on-site in end-user settings such as insulation of residential or commercial buildings and as coatings to protect cement, wood, fiberglass, and metal." [PMID 25563538]

Comments

Diisocyanates, also referred to as isocyanates, are organic compounds with two isocyanate groups (-NCO). They are used to make polyurethane coatings and rigid and flexible foams. Isocyanates are the leading cause of occupational asthma in many post-industrial countries where incidence rates have been measured. Commonly used isocyanates are toluene diisocyanate (TDI), methylene diphenyl diisocyanate (MDI) and polymethylene polyphenyl isocyanate (PAPI). [LaDou, p. 372; LaDou (2nd ed.), p. 521-3] Exposure can occur to vapors at room temperature (TDI and HDI), or after heating (MDI and PAPI), or during spraying processes (all isocyanates). [Sullivan, p. 470-2] "Isocyanate HP," a form of hypersensitivity pneumonitis, has been reported. [Rosenstock, p. 346] Diisocyanates can also cause contact dermatitis (Type IV). [PMID 22411214] "Isocyanates and Work-Related Asthma: Findings from California, Massachusetts, Michigan, and New Jersey, 1993-2008." [PMID 26351141] See "MONOISOCYANATES."

Reference Link #1

Biomedical References

Reference Link #2

Yes

Yes

Yes

Diseases

Occupational diseases associated with exposure to this agent:

• Asthma, occupational
• Contact dermatitis, allergic
• Isocyanate HP

Processes

Industrial Processes with risk of exposure:

• Burning Synthetic Polymers
• Painting (Pigments, Binders, and Biocides)
• Plastic Composites Manufacturing

Activities

Activities with risk of exposure:

• Painting
• Sculpturing plastics