Softening Point Mettler

The softening point of the binder corresponds to its change from solid to liquid state. It is one of the main properties to qualify the binder, as it is usually a production target for the pitch producer and impacts most of the other binder properties. Its level should be chosen to remain below the limits of the thermal capacity of the paste plant to ensure optimum processing conditions.

The measurement is conducted with the RDC-159 apparatus, where a pressed sample (prepared with the RDC-182 apparatus) is placed in a preheated furnace. The temperature is increased with a given heat-up rate until the softened material interrupts a light barrier below the sample. The softening point Mettler is directly read from the display of the equipment and reported in °C.