The effect of fatty acid methyl esters on the curing performance and final properties of thermally cured solvent-borne coil coatings

The solvent content of a thermally cured coil-coating paint may be reduced by introducing a reactive diluent derived from a vegetable oil and thereby producing a coating partly based on a renewable resource. A reactive diluent acts as a solvent in the liquid paint, lowering the viscosity, and is then incorporated into the film during cure. In the present study, rape seed methyl ester (RME) has been evaluated as reactive diluent in a thermally cured hydroxyl-functional polyester/melamine system. RME has suitable diluting properties and functionality to be incorporated into the dry coating. Dynamic mechanical analysis of free standing films shows that the final film properties are affected by presence of reactive diluent, oven temperature, choice of co-solvent, and flash-off period.