Stricter environmental, health and safety regulations, as well as the increased demand for greener products have propelled the development of sustainable coatings. Improved sustainability has been addressed by the coatings industry in various ways. Over the last few years, the trend toward lower-VOC emissions has intensified, and solvent coatings have moved from medium to high solids and solvent-free coatings, or to waterborne technology. Where possible, petrochemical-based products are being replaced with renewable materials that provide good performance. Moreover, aspects such as product durability, energy-efficient processes and transportation are also being taken into account to produce friendlier coatings for the environment.
The transition to low-VOC epoxy coatings has not been without challenges, and in many cases, increase in cost. Paint formulators need to lower viscosity and keep good wetting and leveling properties with or without limited use of solvents. If viscosity is not sufficiently low for conventional spray equipment, pressurized equipment or heated lines are required to apply the coating. That can add to the cost and complexity of the application. In addition, to achieve low-VOC epoxy coatings, it is common to fully or partially replace solvent-based solid epoxies with solvent-free liquid epoxies, which are higher in viscosity and often require the use of diluents. These diluents, especially if non-reactive, are known to typically compromise corrosion performance. Contributing to the challenge, some non-VOC diluents are now considered substances of concern and are in the process of being eliminated in several formulations. Finally, there are a limited number of curing agents in the market that are low in viscosity, free of benzyl alcohol and solvent, and deliver excellent anti-corrosive protection with workable pot life. The curing agent introduced in this article, Cardolite®LITE 3060, enables high-performance, solvent-free epoxy coatings that can be applied by conventional spray equipment.
November is our Emerging Technologies issue. Features include information on new 1K and 2K moisture-curing vinyl alkoxysilane technology, a versatile polymer with self-healing properties, overspray-free painting and a digital formulation assistant for the lab.