Coalescing agents are an inseparable component of latex paints containing polymer dispersions with a minimum film forming temperature (MFFT) higher than the temperature of application and drying of the coatings. In practice, however, in many low-MFFT paints, coalescents are also used to enhance the forming quality of the coating, especially at temperatures below room temperature. Most polymer dispersions used as binders for the production of latex paints have an MFFT of 50 °F to 77 °F (10°C to 25 °C).
Market demands mean that the expected application temperature for paints can usually start at 41 °F (5 °C). This also applies to drying, but it should be kept in mind that during drying, within several minutes or hours, the temperature may drop periodically to below 41 °F (5 °C) and remain at a critical temperature during the coating formation period. Water freezes within 32 °F to 39 °F (0 °C to 4 °C). Effective coalescing action is therefore needed not only in the region just below the film-forming temperature, but also or especially in the critical range for the initiation of freezing of the water.