Product Name
Methylene Diphenyl Diisocyanate
Chemical Name
4,4′-Diphenylmethane diisocyanate
CAS Number
101-68-8
Molecular Formula & Weight
C15H10N2O2 — 250.25 g/mol
Synonyms
MDI, Diphenylmethane diisocyanate, 4,4′-MDI
About MDI
MDI is a pale yellow to brown liquid or solid with a faint odor. It is an aromatic diisocyanate composed of two isocyanate groups attached to a benzene ring system. MDI is primarily used as a building block in polyurethane production, offering durability, insulation, and structural strength across a range of applications.
Applications / Uses
MDI is widely used in the production of rigid and flexible polyurethane systems:
Foams: Core component in rigid polyurethane foams for insulation panels, appliances, and buildings.
- Elastomers: Provides flexibility and wear resistance in wheels, rollers, and automotive parts.
- Adhesives & Sealants: Used in high-strength industrial adhesives and construction bonding systems.
- Coatings: Found in protective coatings that offer abrasion and chemical resistance.
- Automotive: Used in seat cushioning, interior panels, and structural composites.
- Construction: Enables strong, lightweight materials for insulation boards, panels, and roofing systems.
Storage & Handling
- Store in sealed containers at moderate temperatures, away from moisture — MDI reacts with water to form CO₂.
- Avoid contact with heat and incompatible materials such as amines and strong bases.
- Wear protective gloves, goggles, and clothing to prevent skin and eye contact.
- Ensure adequate ventilation and use a respirator if handling large volumes or in poorly ventilated areas.
