Isocyanate Mdi

Cas Number


Other Names




4,4'-Methylene diphenyl diisocyanate

4,4'-Diphenylmethane diisocyanate

Methylene bis(4-phenyl isocyanate)

Pure MDI

The formula



Methylene diphenyl diisocyanate, most often abbreviated as MDI, is an aromatic diisocyanate. Three isomers are common, varying by the positions of the isocyanate groups around the rings: 2,2'-MDI, 2,4'-MDI, and 4,4'-MDI. The 4,4' isomer is most widely used, and is also known as 4,4'-diphenylmethane diisocyanate. This isomer is also known as Pure MDI. MDI reacts with polyols in the manufacture of polyurethane. It is the most produced diisocyanate, accounting for 61.3% of the global market in the year 2000.

Physical and Chemical Properties
Physical state and appearance white to light yellow flakes or crystals
Odor Faint odor
Flash Point 218 C
Boiling Point 194 C at 5 mm Hg
Melting Point 37.2 C
Specific Gravity 1.23 (25°C)
Solubility Insoluble
NCO content, % 31
Viscosity, mP.a.s. 210 (25°C)

MDI is commonly used to manufacture the following types of polyurethane foams:

1. Rigid and semi-rigid

2. Flexible

3. Integral skin

4. Microcellular

MDI is also used to make:

1. Elastomers

2. Coatings

3. Adhesives

4. Binders

5. These products are used in applications ranging from appliances, furniture, and shoes, to decorative molding, boats, and athletic equipment

AUTOTHANE prepolymers – microcellular elastomers for impact, shock, and vibration management in vehicle suspensions and chassis.

DELTA-THERM isocyanates – mining, civil engineering, and pipeline construction.

DIPRANE isocyanates and prepolymers – durable and solvent-resistant elastomers

DUOTHANE prepolymers – sealants, caulking, adhesives, gaskets, wear pads, structural parts.

DURAMOULD isocyanates – cast concrete, rapid prototyping, and tooling industries.

DURELAST isocyanates – furniture edgings.

DYNATHANE isocyanates and prepolymers – elastomers that reduce vibration and noise.

ENFORCER and ENHANCER™ isocyanates – carpet backing.

HYPERKOTE isocyanates – protective coatings designed for industrial and automotive use.

HYPERLAST isocyanates – general elastomers for material handling and industrial engineering.

HYPOL prepolymers – hydrophilic polyurethane foams, elastomers, coatings, adhesives, or gels.

ROTAKOTE prepolymers – elastomers for rotational coatings.

SPECFIL isocyanates – widely used by the automotive industry for filter gasketing (oil, fuel and air), for the production of industrial filters, for in-situ gasketing applications, climate control systems, ventilation systems, and as dust filters in respiration masks.

SPECFLEX isocyanates – flexible and integral skin foams used in the furniture and transportation industries for steering wheels, automotive seating, headrests, and dashboards.

SPECTRIM isocyanates – reaction moldable products for the transportation industry such as bumpers, rocker panels, spoilers, and grills.

TRAFFIDECK isocyanates and prepolymers – waterproofing and surfacing systems for parking decks, roofs and balconies, bridges, and marine use.

VORACOR isocyanate –rigid foam insulation for the construction industry, commercial refrigerators, water heaters, pipeline insulation, roofing, manufactured housing and modular construction.

VORALAST isocyanate – lightweight expanded microcellular foam for any type of footwear soling such as sandals, slippers, and midsoles for sport shoes.

VORALUX isocyanate – high-resilience foam for furniture and automotive pillars

VORAMER isocyanates – adhesives and binders in a variety of recycling .applications, bonding together different kinds of shredded materials such as rubber, flexible polyurethane foams, ethylene-vinyl acetate (EVA), cork and gravel.

VORASTAR isocyanates – elastomers used for the furniture and decorative industries; coatings, adhesives, sealants, and elastomers (CASE); mining and transportation industries.

VORATEC isocyanates – expanded rigid foams used for commercial refrigerators, freezers.

water heaters, portable appliances, and prefabricated panels.

VORATRON isocyanates – elastomers and casting resins for electronics and electrical Insulation.

XiTRACK isocyanates – rail stabilization through treatments that improve track quality.