What role do solvents play in paints and other surface coatings?

In surface coatings, solvents and carrier liquids serve as essential media for dissolving or dispersing polymers, pigments, and additives, allowing the coating to be manufactured and applied in a liquid form.12

Their primary roles include:

• Application and Flow: Solvents reduce the viscosity of the coating, enabling it to be brushed, sprayed, or applied via industrial processes.32
• Film Formation: In evaporation-based processes, the solvent acts as a temporary vehicle that holds the polymer in solution; once applied to a substrate, the solvent evaporates, leaving behind a solid, adherent film.43
• Manufacturing: Solvents are often required during the synthesis of the polymers themselves and are crucial for ensuring the proper solubility of the final coating formulation.1

While effective, the use of organic solvents is strictly regulated due to their status as volatile organic compounds (VOCs), which contribute to air pollution. Consequently, the industry has shifted toward high-solids coatings or water-based systems, where water serves as the carrier liquid to minimize environmental impact.13