United States Commerce Department Rules China MDI Dumping Margin Up To 512%! (Including China-US MDI Trend Changes)

Recently, the U.S. Department of Commerce announced a positive preliminary determination of anti-dumping duties on diphenylmethane diisocyanate (MDI) originating from China.

In the preliminary anti-dumping announcement, the U.S. Department of Commerce determined that the dumping margin for Chinese MDI is as high as 511.75%.From the date of the preliminary anti-dumping announcement, the U.S. Department of Commerce will instruct U.S. Customs and Border Protection (CBP) to collect temporary anti-dumping duties in the form of cash deposits based on the dumping margins of the relevant producers/exporters involved.

The weighted average dumping margin determined in the preliminary anti-dumping ruling is as follows:

The product involved in the preliminary anti-dumping ruling is diphenylmethane diisocyanate (MDI), including polymeric MDI, pure MDI, and modified MDI.

MDI is a versatile chemical intermediate used in the production of various insulation materials such as rigid foam plastics; flexible foam plastics for automotive seats, bedding, and furniture; as well as in coatings, adhesives, sealants, and elastomers.

The physical forms of MDI range from low-viscosity liquids to solids. Regardless of whether the MDI has undergone a distillation process, and regardless of its acid content, reactivity, functionality, freeze stability, physical form, viscosity, grade, purity, molecular weight, or packaging, it is included within the scope of this investigation.

MDI may contain additives such as catalysts, solvents, plasticizers, antioxidants, flame retardants, colorants, pigments, diluents, thickeners, fillers, softeners, and tougheners. Mixtures of MDI with other materials, where MDI constitutes less than 40% of the total weight of the mixture, are not within the scope of this survey.

MDI can partially react with itself, polyols, or polyamines, retaining unreacted MDI components, thereby transforming it into different products that no longer contain isocyanate groups. Among these products, if the NCO content is less than 10% of the total weight, they are not within the scope of this investigation.

The scope of this investigation includes goods processed in a third country that match the above description, including mixing, diluting, introducing or removing additives, or any other processing, which, if conducted in the target country, would not remove the goods from the scope of the investigation.

The product can currently be classified under the U.S. Harmonized Tariff Schedule (HTSUS) codes 2929.10.8010 and 3909.31.0000. Related goods can also be classified under the codes 3506.91.5000, 3815.90.5000, 3824.99.2900, 3824.99.9397, 3909.50.5000, 3911.90.4500, 3920.99.5000, and 3921.13.5000.

During former President Trump's first term in the United States, MDI was already subject to the initial 301 tariffs on China (25%). In 2025, President Trump imposed so-called "reciprocal tariffs" on all Chinese imports. Although the current trade agreement between China and the United States decided to suspend the implementation of the 24% tariffs for 90 days starting from August 12, 2025, an additional 10% tariff on all Chinese imports remains in place.

This means that, in addition to the basic tariff of 6.5%, China's exports of MDI to the United States are already facing a total tariff of 41.5%. Under this tariff level, Chinese exports to North America still maintain a certain level of competitiveness compared to European sources.

If the US Department of Commerce makes an affirmative final determination later, it is expected to have a limited impact on Chinese MDI manufacturers. Facilities in the East Asia region, such as Kumho Mitsui (610,000 tons/year) and BASF Korea (250,000 tons/year), may increase their export efforts to the US, which will lead to a tightening of supply in the Asia-Pacific foreign trade market. Wanhua Chemical's products are expected to fill the market gap in the Asia-Pacific region. Moreover, Wanhua Chemical has an MDI production capacity of 400,000 tons in Europe (BorsodChem in Hungary), which is likely to mitigate related risks by increasing exports from European facilities to the US. This may reshape MDI trade flows, but it will not change the global MDI supply pattern in recent years.

Source: Official websites of customs from various countries, compiled by Orisage Consulting.