Wanhua Chemical Group Co. Ltd. is seeking public feedback on its draft environmental impact report for a proposed expansion of its hexamethylene diisocyanate (HMDI) production in Yantai Chemical Industry Park, according to a notice posted on the company's official website Monday.

The project, situated within the Wanhua Yantai Industrial Park, involves increasing the capacity of the existing HMDI unit from 20,000 tons per year to 40,000 tons per year. Additionally, the expanded unit will also produce 30,000 tons per year of hydrogenated diphenylmethane diisocyanate (HDI). The plans also include the construction of a hydrogen chloride (HCL) refining unit.

Wanhua Chemical indicated that existing infrastructure within its current plant, such as the tank area and loading and unloading stations, along with existing environmental protection facilities, will support the expanded operations.

HMDI, also known as 4,4'-dicyclohexylmethane diisocyanate or H12MDI, is an alicyclic diisocyanate chemically similar to methylene diphenyl diisocyanate (MDI). However, HMDI features a cyclohexyl ring instead of a benzene ring in its structure. Polyurethane products derived from HMDI are known for their superior light stability, weather resistance, mechanical strength, hydrolysis resistance, and chemical resistance. These properties make HMDI particularly well-suited for manufacturing polyurethane elastomers, water-based polyurethanes, fabric coatings, and radiation-cured polyurethane-acrylate coatings.

HDI, a related chemical, currently sees major global production from companies such as Covestro, with a capacity of 190,000 tons per year, and Kangrui, possessing a 70,000 tons per year capacity. Other significant producers include Tosoh, with 30,000 tons per year (including technological upgrades), Asahi Kasei at 22,000 tons per year, and Wanhua itself, which has a current and planned/upgraded capacity of 260,000 tons per year. Meirui New Materials has a Phase I capacity of 100,000 tons per year, and Xinhecheng has a planned capacity of 100,000 tons per year. Notably, much of the recent growth in HDI production capacity globally has been concentrated within China.

Polyurethane is a high-molecular-weight polymer formed through a chemical reaction between isocyanates—such as MDI, TDI, and ADI—and polyols, along with various additives. Isocyanates serve as the primary raw materials in polyurethane production. Aliphatic isocyanates, collectively known as ADI, include key types such as isophorone diisocyanate (IPDI), 1,6-hexamethylene diisocyanate (HDI), and dicyclohexylmethane diisocyanate (H12MDI).

The public notice from Wanhua Chemical invites stakeholders to submit their opinions and feedback on the draft environmental impact report for the HMDI expansion project. The company has not specified a deadline for the submission of these opinions in the publicly available notice.