ASTM D3104 Standard Test Method for Softening Point of Pitches (Mettler Softening Point Method)
9. Procedure
9.1 The procedure described in this test method for measuring the softening point of pitches using either METTLER TOLEDO instrument has been developed to duplicate the results obtained by Test Method D2319.
9.2 Old Instruments - Preset the temperature of the furnace to 20 °C to 25 °C below the expected softening point of the sample and maintain this temperature for a few minutes (see Note 1). Place the sample cup in the cartridge and the cartridge assembly in the furnace, taking care that the slits for the light beam are properly positioned. Wait for temperature equilibration, that is, the furnace and the sample are in equilibrium at the preset temperature, but not less than the 30 s after inserting the cartridge, start the automatic heating cycle at 2.0 °C/min. Heating will be maintained at this rate until the drop point is reached, after which a steady temperature will be displayed on the digital readout. Record this temperature as the softening point of the sample.
NOTE 1 - In the event of a dispute, the purchaser and supplier shall agree on the exact starting temperature to be used.
9.3 Old Instruments - Immediately remove the cartridge assembly upon completion of the test. Check to ensure that the sample has passed the light beam and no pre-triggering has occurred. If a malfunction is suspected, reject the result and repeat the test. Inspect the apparatus closely to ensure that no particles of residue remain.
9.4 New Instruments - Preset the temperature of the furnace to 20 °C to 25 °C below the expected softening point of the sample and maintain this temperature for a few minutes (see Note 2). Place the sample cups in the sample carrier and the sample carrier assembly in the furnace. Wait for temperature equilibration, that is, the furnace and the sample are in equilibrium at the preset temperature, but not less than the 30 s after inserting the cartridge, start the automatic heating cycle at 2.0 °C/min. Heating will be maintained at this rate until the softening point is reached, after which a steady temperature will be displayed on the digital readout. Record this temperature as the softening point of the sample.
NOTE 2 - In the event of a dispute, the purchaser and supplier shall agree on the exact starting temperature to be used.
9.5 New Instruments - Immediately remove the cartridge assembly upon completion of the test. Check to ensure that the dropped and no pre-triggering has occurred. The video may be viewed to make sure the drop was detected correctly. If a malfunction is suspected, reject the result and repeat the test. Inspect the apparatus closely to ensure that no particles of residue remain.
9.6 Clean the sample cups by placing them upside down on a hard surface and punching out any residual material. Use a spatula, shaped to the contour of the cup, with a swirling motion to remove any remaining particles. Washing with xylene, or other suitable solvent, may be necessary to get the apparatus completely clean.
