Unsaturated polyester resins (UP) have a wide market as particle adhesion materials, coatings and structural materials. UP are typically prepared through simple esterification reactions between alcohols and carboxylic acids. Since monomer mixtures are frequently used, reactions become more complex by the different combination possibilities and secondary reactions.
Common commercial UP resins use raw-materials derived from petroleum, using quite old polymerization technologies.
Nowadays, consumer and authorities’ pressure towards cleaner technologies and with greener raw materials bring enormous challenges to the industry. In addition, unstable prices in oil derived raw materials add pressure to the development of new alternatives.
At the beginning of the project no solution in the market was found with more than 50 % of green raw materials. To increase this value, alternative raw materials must be found and their reactivity studied in UP processes. Another important goal of this project is the styrene replacement as the crosslinking agent of UP resins, without substantial changes in properties and cost. Curing kinetics must be kept, thus avoiding possible modifications of industrial processes while keeping final product specifications.
The characteristics of each unsaturated polyester application have impact on the polymer reactivity and its reactive solvent. For instance, resins with higher contents of unsaturated monomer generate a denser crosslinked network, with higher chemical resistance. Adjustments on flexibility and other mechanical properties can be made through alcohol composition variation. The introduction of uncommon structure monomers can lead to a complete reformulation of the rest of the composition, in order to achieve the desired properties for each application.