An overview of epoxy resins and hardeners
Epoxy groups as crosslinked building blocks – These are so many resins available that can contain epoxy groups that it is really necessary to classify the epoxy products that available on the market. ISO 3673-1:1999 classifies these epoxy resins by their chemical structure and possible additives, and then further divides them within those categories into their specific types, i.e. aliphatic, aromatic and nitrogen-containing compounds.
ISO 4597-1:2010-01 classifies hardeners for epoxy resins and distinguishes between those which are able to react with epoxy groups on one hand and those, which are able to react with the hydroxyl groups of phenoxy resins on the other.
A notable feature is the careful distinction drawn for polyamide-amine hardeners, which are classified first into aromatic and aliphatic types and then by additive and filler.
It is worth noting as we that ISO 3673-1:1999 fails to classify groups of binders that do not have epoxy groups, (i.e. phenoxy resins) whereas ISO 4597-1:2010-01 classifies formaldehyde resins and isocyanates as hardeners. This might suggest that phenoxy resins should be classified under epoxy resins.