Aliphatic diisocyanates monomers are key raw material for aliphatic polyurethanes.
Due to their specific toxicological profilethe aliphatic diisocyanate monomers are typically not used as such in the final application. In fact the diisocyanates are converted by the chemical industry into so-called polyisocyanates , which contain only very small amounts of free diisocyanate monomer, or into aliphatic polyurethane resins, in which often all isocyanate groups are used up to impart other functionalities into such resins. Examples for the latter of which are waterborne polyurethane dispersions, radiation curable urethane acrylates or thermoplastic polyurethanes. Polyisocyanates are crosslinking compounds in so-called 2-pack or 2-component polyurethane coatings. Further derivatization of polyisocyanates leads to blocked polyisocyanates which are relevant in certain stoving applications of coatings.
The most relevant products in this sector are:
- Hexamethylene-diisocyanate-1,6 (HDI)
- Isophorone Diisocyanate (IPDI)
(3-Isocyanatomethyl- 3,5,5- trimethyl- cycohexylisocyanate),
mixture of cis-and trans isomers CAS-No. 4098-71-9
- 4,4′- Dicyclohexylmethane-diisocyanate
(H12-MDI), main component, mixture of isomers
More details can be found in the following safety information sheets: