Vinyl ester polyester is also called acrylic polyester resin, vinyl ester unsaturated polyester resin or epoxy acrylic polyester resin. In terms of molecular structure, the macromolecule of vinyl ester polyester contains both the main chain structure of the epoxy resin molecule and the polyester structure with unsaturated double bonds. Therefore, vinyl ester polyester has both good adhesion and mechanical strength of epoxy resin, and good curing properties of unsaturated polyester resin. Especially outstanding is that in terms of corrosion resistance, it is not only better than ordinary unsaturated polyester resins and epoxy resins, but also better than phenol A-type unsaturated polyester resins in certain media. This is because vinyl ester polyesters are different from ordinary unsaturated polyesters whose main bonds contain cyclic ester groups. The former contains only terminal ester groups in the molecule, and the concentration of ester groups (means the average number of ester groups per 100g of unsaturated polyester resin Moles) is lower. The ester group is a weak structure in terms of corrosion resistance, and the less the ester group, the higher the corrosion resistance. In addition, its ester group has a methyl group on the adjacent carbon atom, this methyl group can play a role in protecting the ester group.
In the presence of a catalyst, vinyl ester resins are prepared by addition reaction of various unsaturated monocarboxylic acids and various epoxy resins, and the grades of the vinyl resins used are different.
Phenolic epoxy type vinyl ester resin such as W 2-1 resin is a new type of vinyl ester resin produced by the reaction of novolac epoxy resin and unsaturated monocarboxylic acid (acrylic acid).
Because the resin has a large number of benzene rings in the macromolecular chain, and the crosslink density is relatively higher than that of general general unsaturated polyester, the resin has better heat resistance and thermal rigidity after curing, measured according to ASTMYO-684 method The heat distortion temperature is 122°C. The data shows that the strength retention rate can still reach 75% at 120°C.