As the most important component–emulsions for coatings and polymer dispersions for coatings and plastics polymer, its film-forming property has an important influence on the final products drying property. Thus, knowing its MFT is very necessary.
At a certain temperature, emulsions or polymer dispersions, if the temperature is not high enough, then can’t let the polymer particles polymerize. Now, all polymer particles can’t get together any more and then form incontinuous and non transparent white mass; If the temperature is high enough and let the particles get together, then can form a continuous and transparent film.
White Point Temperature: The dividing temperature when non-transparent film change to transparent film.
Minimum Film-forming Temperature : The lowest temperature when forming continuous, uniform and no-crack film Generally speaking, White Point Temperature has serval degrees lower than MFFT
BGD 452 Minimum Film-Forming Temperature MFFT Tester: is the newest instruments which is developed by Biuged lately, Its main structure is a metal copper platen with an electronically imposed temperature gradient.
Built in temperature sensors monitor the temperature across the platen, a graph of the gradient is displayed on the touch screen. A cooling source and a heating source are located separately on the two ends of platen to produce different temperature gradients through metal heat conduction theory.
Applicate a continuous and uniform thickness wet film of emulsion or dispersions on the temperature gradient platen, then dry it by dry air, with temperature of platen influence, the water of sample would evaporate and form film. Due to different temperature on the platen, the film-forming position is also different. Find the dividing point between continuous transparent film with white non-transparent film, thus this point which also can be read from touch screen of tester is MFFT. It is accordance with ISO 2115, ASTM D 2354 standard, and can test minimum film temperature of emulsion polymer easily and accurately.