The behavior of MEKO-blocked isocyanate compounds in aluminum flake pigmented, polyester–polyurethane can coating systems

Information is given concerning the curing characteristics of polyester–polyurethane (PEPU)-based food can coatings and the analysis of the free isocyanate by-products. The behavior of a methyl ethyl ketoxime (MEKO)-blocked isocyanate on heating was studied using thermal analytical techniques. Following this, the curing behavior of a PEPU-based can coating (PEPU01 that contained an aluminum flake pigment) and the MEKO-blocked isocyanate was investigated. A study of the unblocking of the MEKO-blocked isocyanate in the PEPU01 can coatings was undertaken with respect to the migration potential of any residual-free isocyanate compounds that could migrate from the cured PEPU can coatings to the surrounding medium (e.g., foodstuffs).