Reading the tech pages for the unimold system I understand that vinylester is used instead of polyester etc.  Vinyl ester is more hydrophobic, tougher, and heat resistant which is ideal for our of autoclave use i.e.. pre press, etc.  My question is, is vinylester used in all the resins including gelcoats, tooling coat and so on or is it just used as the resin for mating the fiberglass to the gelcoat?  If this is the case what kind of gelcoats are being used and why would they hold up to higher heats if vinylesters are used otherwise?  Thank you for any insight you might have.

The tooling gelcoat and the coupling coat are vinyl ester. The tooling resin is a specialised polyester resin which contains a filler that expands at the same rate the resin shrinks.