The MFT is the lowest temperature required to coalesce the polymer applied to the substrate into a thin film. When applying a coating, the minimum film formation temperature of a polymer is very important to know and understand in order to avoid coating failure.
If the polymer is applied to a substrate and the temperature is below the minimum film forming temperature, it may not cure properly and the coating will often crack. This does not occur if the minimum film formation temperature is met or exceeded.
While the MFFT for a given polymer coating can be approximated by calculation, one of the better ways to measure it is with a MFFT stick, which is a device consisting of a platen and a heating element. The material to be analyzed is applied to the press plate in very thin layers. Then, the bar platen with the lowest film-forming temperature heats the material. When coalescence occurred, the temperature was recorded.
