I believe that isocyanate is a primary component in most 2K products. It's the main ingredient in the hardeners. If you use Acrylic Enamel, you don't need to use the hardner. It doesn't work the same in Acrylic Enamel as it does in epoxy products so you can do without it but it takes longer to fully harden.
Mike
I always thought hardener was used to enhance gloss as much as anything else.
