Chinese polyurethane chemicals maker Wanhua has exercised an option that will give it control of the Hungarian isocyanates and vinyls maker BorsodChem. Wanhua says the purchase will make it the third-largest isocyanates producer in the world. Wanhua acquired the option to buy the shares from the private equity firms Permira and Vienna Capital Partners last year when it provided $190 million to BorsodChem. The firm is using the money to complete toluene diisocyanate (TDI) and nitric acid plants in Hungary. BorsodChem had sales of about $860 million in 2009. Wanhua is building a TDI and methylene diphenyl diisocyanate (MDI) complex in China that will give it 1.5 million metric tons of isocyanate capacity.