Search results
Results from the WOW.Com Content Network
Methylene diphenyl diisocyanate (MDI) is an aromatic diisocyanate. Three isomers are common, varying by the positions of the isocyanate groups around the rings: 2,2′-MDI, 2,4′-MDI, and 4,4′-MDI. The 4,4′ isomer is most widely used, and is also known as 4,4′-diphenylmethane diisocyanate. [3] This isomer is also known as Pure MDI.
The global market for diisocyanates in the year 2000 was 4.4 million tonnes, of which 61.3% was methylene diphenyl diisocyanate (MDI), 34.1% was toluene diisocyanate (TDI), 3.4% was the total for hexamethylene diisocyanate (HDI) and isophorone diisocyanate (IPDI), and 1.2% was the total for various others. [18]
Hydrogenated MDI (H 12 MDI or 4,4′-diisocyanato dicyclohexylmethane) is an organic compound in the class known as isocyanates. [1] More specifically, it is an aliphatic diisocyanate. It is a water white liquid at room temperature and is manufactured in relatively small quantities.
[3] MDA is a common monomer in the synthesis of polymer materials. These include polyamides, [4] polyimides and polyimines. [5] MDA is also used extensively as a precursor to methylene diphenyl diisocyanate (MDI). Here, MDA is treated with phosgene to produce MDI. MDI, in turn, is a precursor to many polyurethane foams.
A diisocyanate, often 4,4’-methylenediphenyldiisocyanate (MDI), is reacted with trimellitic anhydride (TMA). The product achieved at the end of this process is a high molecular weight, fully imidized polymer solution with no condensation byproducts, since the carbon dioxide gas byproduct is easily removed.
Skeletal formula of 4,4'-methylene diphenyl diisocyanate (4,4'-MDI, Pure MDI). Created using ACD/ChemSketch 10.0 and Inkscape. Date: 5 October 2007: Source: Own work: Author: Fvasconcellos 16:37, 6 October 2007 (UTC) Permission (Reusing this file)
The shares started to trade in the Shanghai Stock Exchange in January 2001. Initially, the listed company only owned the methylene diphenyl diisocyanate (MDI) production line of the former Yantai synthetic leather factory. [4] It was a common practice at that time to list part of the assets instead of the whole conglomerate.
In chronic toxicity tests, mice exposed to low levels of PPI developed no side effects. Only those mice exposed to the two highest concentrations developed any lung symptoms. [3] The two highest doses used in this study were 1.0 and 6.0 mg per cubic meter for 6 hours each day, 5 days each week for 2 years.