Methylene bis (phenylisocyanate) is used in the making of polyurethane foams and other synthetic components of furniture, machinery and electrical components for a variety of household and other electrical appliances. It is used to bond rubber to other synthetic fibres such as rayon and nylon. Also used in specialised spray paints, surface coatings, man-made resin and artificial gum. Some printers' ink may contain the compound. It is used in metal foundries to bind materials in low-temperature curing of metal components.
Substance name: Methylenebis (phenylisocyanate)
CASR number: 101-68-8
Molecular formula: C15H10N2 O2
Synonyms: Isocyanic acid, methylenedi-p-phenylene ester mdi benzene, 1,1'-methylenebis(4-isocyanato)- (9ci) methylenebis (4-isocyanatobenzene) bis(p-isocyanatophenyl)methane 1,1-methylenebis(4-isocyanatobenzene) bis(1,4-isocyanatophenyl)methane methylenebis(p-phenylene isocyanate) methylenebis(4-phenylene isocyanate) bis(4-isocyanatophenyl)methane p,p'-methylenebis(phenyl isocyanate) caradate 30 desmodur 44 4,4'diisocyanatodiphenylmethane 4,4'-diphenylmethane diisocyanate diphenylmethane-4,4'-diisocyanate hylene m50 isonate 125m isonate 125mf methylenebis(p-phenyl isocyanate) methylenebis(4-phenyl isocyanate) 4,4'-methylenebis(phenyl isocyanate) 4,4'-methylenediphenyldiisocyanate methylenedi-p-phenylene diisocyanate methylenedi-p-phenylene isocyanate 4,4'-methylenediphenylene isocyanate nocconate 300 nci-c50668, MDI.
Insoluble brown liquid, yellow to white crystals or solid at normal temperatures.
Melting Point: 37.2°C
Boiling Point: 196°C
Specific Gravity: 1.197
Vapour Density: 8.6.
A stable solid under normal conditions in the atmosphere, insoluble in water but soluble in solvents such as acetone, kerosene and benzene. Will react vigorously with alcohol, acid and some other compounds.
The National Pollutant Inventory (NPI) holds data for all sources of Methylenebis (phenylisocyanate) emissions in Australia.
This depends on how much methylene bis (phenylisocyanate) you have been exposed to, for how long, and your current state of health. In certain circumstances, even a brief exposure to very high levels of methylene bis (phenylisocyanate) can result in skin and other irritations and affect breathing capacity. Exposure can result in symptoms such as skin dermatitis, nose, throat, lung and eye irritations. If it is inhaled as a dust it can cause shortness of breath, wheezing, coughing and chest tightness, headache and nausea.
Entering the body
Can be inhaled as minute dust particles or in the form of a fine spray mist. May result in irritation when in contact with the skin or eyes.
People may be exposed to very low levels of Methylene bis (phenylisocyanate) from direct contact with freshly manufactured or produced products that contain it. People working in or living near industries that produce or use it may be subject to low but persistent exposure to minute amounts of dust particles. Exposure is limited to areas where it is used or manufactured.
Workplace exposure standards
Safe Work Australia sets the workplace exposure standard for isocyanates (including methylenebis (phenylisocyanate)) through the workplace exposure standards for airborne contaminants:
- Maximum eight hour time weighted average (TWA): 0.02 mg/m3
- Maximum short term exposure limit (STEL): 0.07 mg/m3
These standards are only appropriate for use in workplaces and are not limited to any specific industry or operation. Make sure you understand how to interpret the standards before you use them.
Drinking water guidelines
There is no guideline for methylenebis (phenylisocyanate) in the Australian Drinking Water Guidelines.
Methylene bis (phenylisocyanate) is known to result in lung damage to humans. Similar results are evident for some other animals but only where the compound has been inhaled as dust particles or an aerosol.
Entering the environment
Methylene bis (phenylisocyanate) is a solid, or less commonly a sticky liquid, and will gradually react with acid or basic compounds in the atmosphere, or in the soil into less complex compounds such as urea, amine and carbon dioxide. It will generally be transported in the atmosphere as dust particles or as a component of an aerosol but that only occurs within or surrounding manufacturing or production plants where it is used.
Where it ends up
It will remain as a solid at normal temperatures and may gradually breakdown as result of contact with organic compounds in the soil or atmosphere. It will give rise to carbon dioxide and other compounds of nitrogen, carbon, hydrogen and oxygen as result of slow gradual breakdown through contact with the atmosphere.
No national guidelines.
It may be emitted to air, land or water from locations that produce polyurethane foam, adhesives, resins and plastic coatings, or where large volumes of polyurethane spray paint are used such as, vehicle manufacturing and repair workshops, vehicle body shops and specialised marine dockyards.
Diffuse sources, and industry sources included in diffuse emissions data
Trace amounts may enter the natural environment from the wide variety of uses and applications. Minute quantities may be derived from the widely distributed consumer products that use polyurethane foam, adhesives and coatings.
No natural sources.
No mobile sources.
Polyurethane foam, surface coatings, sprays paint, synthetic components of household furniture and a variety of electronic components and accessories where polyurethane products are present.
Sources used in preparing this information
- ChemFinder WebServer Project (1995) (accessed, 30 May, 1999)
- Environmental Defense Fund (1998), Consumer Products, Chemical Profile (accessed, 30 May, 1999)
- National Environment Protection Council (1998), National Environment Protection Measure for the National Pollutant Inventory. (accessed, March, 1999)
- Technical Advisory Panel (1999), Final Report to the National Environment Protection Council.
- United States National Toxicology Program. Chemical Status Report. NTP Chemtrack System. Research Triangle Park, NC. November 6, 1990. (accessed, 30 May, 1999)
- Safe Work Australia, Workplace exposure standards for airborne contaminants, accessed January 2019.
- National Health and Medical Research Council (NHMRC), Australian Drinking Water Guidelines (2011) - Updated October 2017, accessed May 2018.