Mitsui Chemicals to boost MDI capacity at South Korea plant
Kumho Mitsui Chemicals, an affiliate of Mitsui Chemicals, plans to further increase the capacity of its production facilities for methylene diphenyl diisocyanate (MDI) in its site at Yeosu, Jeonnam, South Korea.

Kumho Mitsui Chemicals’ Yeosu plant.
Construction of the expansion is expected to start in February 2026 and complete in May 2027. With the expansion, the capacity for MDI will increase by 100,000 tons per year, with a total annual capacity of 710,000 tons of MDI.
Manufacturing and recycling in one facility
Kumho Mitsui Chemicals manufactures and sells high-performance monomeric, modified, and high-viscosity polymeric types of MDI used for making auto parts, elastic fibers, and highly flame-retardant insulation materials, as well as commodity polymeric MDI used for making housing and home appliance insulation.
The facility is already operating at full capacity following a 200,000-ton capacity increase in 2024. With this new capacity increase, Kumho Mitsui Chemicals will be able to accommodate growing demand for not only automotive materials, but also the high-performance MDI used in flame-retardant insulation materials.
Furthermore, this move will make full use of the recycling facilities introduced during the previous 200,000-ton capacity increase, reducing GHG emissions per unit of MDI produced.
More on methylene diphenyl diisocyanate (MDI)
MDI is a key raw material for polyurethane, widely used in automotive parts, furniture and bedding, insulation for homes and refrigerators, elastic fibers, and various adhesives.
Demand for MDI is projected to grow at an annual rate of 5% going forward on account of policy measures around the globe to improve residential insulation as a means of global warming suppression, as well as due to the heightened demand accompanying economic growth.