| abstract |
This disclosure relates to a composition comprising (a) 4,4'-methylene diphenyl diisocyanate (4,4'-MDI), and (b) at least one heterocyclic compound comprising as ring moiety at least one structure of formula (I) as defined in the description. The heterocyclic compound can suppress the formation of 4,4'-MDI dimer and thus prevent the formation of insoluble solids and extend the shelf life of 4,4'-MDI. |