Isocyanates (TDI / MDI)​

TDI (Toluene Diisocyanate) and MDI (Methylene Diphenyl Diisocyanate) are the two most widely used aromatic isocyanates in polyurethane manufacturing. As core reactive partners to polyols, they form the backbone of polyurethane chemistry and significantly influence processing behavior and final material performance.

TDI is predominantly utilized in flexible polyurethane foam production due to its high reactivity and ability to generate soft, resilient cellular structures. Commercial grades—typically 80/20 and 65/35 isomer blends—allow formulators to tailor foam properties such as compression set, airflow, and durability. TDI’s reactivity profile makes it well-suited for slabstock foams, molded foams, and various cushioning applications in furniture, bedding, and automotive interiors.

MDI offers a broader performance envelope and is available in both pure monomeric and polymeric (pMDI) forms. Monomeric MDI provides controlled reactivity, excellent mechanical properties, and superior bond strength, making it a preferred choice for high-performance elastomers, adhesives, and coatings. Polymeric MDI, characterized by higher functionality and viscosity, is widely used in rigid foam systems—especially insulation panels, spray foam, and structural composites—where dimensional stability and thermal efficiency are critical.

Key attributes such as isocyanate content, viscosity, functionality, and reactivity determine the formulation window and end-use performance. Together, TDI and MDI enable precise engineering of polyurethane systems across industrial, automotive, construction, and consumer markets, making them indispensable components of modern polyurethane technology.