Minimum film forming temperature (MFFT) tester – SAMFT452
This instrument is employed for determining the minimum film-forming temperature.
A painting emulsion is made up of solid particles of resin and fillers dispersed in water. In order to form the film, it is necessary for resin particles to get closer until touch each other thanks to water evaporation. It is very important to know the filming temperature because it represents the minimum temperature below which a painting emulsion is not able to give a continuous film without cracks.
The minimum film-forming temperature (MFFT) of a varnish or coating is the minimum temperature to which the product, applied on a substrate, coalesces in the form of a homogeneous and transparent film. The product is applied on a nickel-coated copper top to which a temperature gradient is applied electronically. 16 sensors control and regulate the temperature along the surface, while a flow of dehydrated air is made to flow along the surface itself to prevent the formation of frost.
A transparent protective cap covered the surface, thermally isolating it from the outside, but allowing visual inspection. Manual movement of a cursor at the point where, visually, the beginning of the coalescence process (formation of a transparent film) is highlighted determines the minimum film-forming temperature.
The machine calculates and displays the corresponding temperature data on the touchscreen.