Less than perfect mix of epoxy, is it safe?

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#1

Hi,
Does anyone know what actually happens with the uncured parts of an epoxy laminate, from a safety perspective? Since perfect dosing/mixing doesn’t exist (in my mind anyway) there must be some amount of unmixed/unmatched molecules left in the laminate. Very little information can be found about this.

Since most hardeners are quite reactive (and probably give allergy over time) it seems to me that having less than perfect cured laminates would not be entirely safe to handle. Or maybe it’s contained well inside the laminate to never cause a problem? After all it does turn into a solid.

#2

I believe your referring to “green” laminate". After a good post cure, the laminate will be much safer to handle.

#3

From some reading I did a long, long time ago into coating water tanks. There is not too many issues with reducing the hardener content to the absolute minimum ratio to complete polymerisation. In tanks, it is done to reduce the contamination risk.

Theory goes:
The chemical reaction between the hardener and the resin will continue until the hardener ‘molecules’ as you described have all attached to the resin molecules.
The matrix becomes inert thereafter.

If you increase the hardener content or “overdose” then the situation you describe is real.
If the hardener ratio is above optimum, then the hardener molecules run out resin molecules to react with. Then the hardener is left in the matrix unchanged.

If possible never overdose your resins thinking it is better, actually the opposite is chemically better.