Vinylester resins were developed as the middle ground between Polyester Resins and Epoxy. They combine the advantages of Epoxy with the better handling and faster cure times of typical polyester resin. They can be reinforced with glass fibres and carbon fibres. They are a step up in cost compared to Polyester resins. Vinylesters exhibit excellent resistance to water, organic solvents and alkalis, but less resistance to acids than polyesters.
Vinylesters are similar to Polyester in terms of molecular structure but the primary difference is that their reactive sites are present at the end of molecular chain. Since the whole length of the molecular chain is available for shock loading, is makes Vinylester resins tougher and more resilient than polyester resins. Their flexible nature produces parts that withstand impacts and repeated flexing without developing cracks. For Vinylesters, the moulding conditions are similar to those for Polyesters.
Being tougher and suffering from shrinkage while curing due to their double bonded nature, it is difficult to achieve surface quality as good as Polyester.
Used in corrosion resistant industrial tanks, pipes, marine application, pultruded profiles etc.
The best process for producing your product depends upon the design of the product (its physical properties and dimensional tolerances), production volume and your tooling budget.
Some of the processing technologies for Polyester resins are given below.