The benefits included an elimination of VOC's from the assembly area, reduced price, increased strength, and elimination of shrink problems from the bond line. New generation epoxies feature many of the advantages of low viscosity and accurately tailored gel and cure times. Permanent repairs and the highest quality custom aerospace construction have been enjoying the advantages of epoxies since the sixties. MAS brings these advantages the builder and repairer at room temperatures in the nineties and are gearing up more surprises for 2000 and beyond. These hybrid resins are toughened with epoxy molecules within the backbone.
Shrinkage is less of a concern with vinylesters and prerelease of the part from the mold is reduced.
The toughening effect of the resin modifications makes for a better resistance to micro fracturing and some of the secondary functionality of the backbone assists in adhesion to substrates. Resistance of vinylester resin to moisture is good and some commercial barrier coatings have been marketed utilizing this resin family. Good tough vinylester is also quite pricey when compared to polyesters, in fact the dollars per pound approach that of epoxies. Vinylesters definitely represent an improvement over polyesters when considering standard peroxide curing, however adhesion to dissimilar and already cured substrates is still far below perfect and many vinylester hulls suffer similar massive delamination of the hull skins from core and bulkhead substrates. Additionally since almost all barrier-coating applications are after market it is essential that the coating system have maximal bonding strength to the original substrate.