A New Device for Measuring Shear Viscosity of Rubbers on a Rubber Injection Molding Machine

Michael Fasching, Walter Friesenbichler, Eduard Leitner, Gerald Berger

    Research output: Contribution to conferencePaperpeer-review


    The measurement of shear viscosity for rubber compounds is a challenging task, as the contribution of the fillers like carbon black or silica to the measurement result is dependent on the material prehistory. Thus, the capillary rheometer and especially the rubber process analyzer show different measurement results compared to what is observed in the actual injection molding process. This work presents the development of a new rheometric injection mold which is mountable on a standard rubber injection molding machine and therefore allows the measurement of the material condition of the actual injection molding process (taking into account effects of shear forces of dosing screw). The fixed half, where the shear viscosity measurement is carried out, is equipped with a rectangular slit and 4 pressure sensors as well as 2 heat flow sensors to be able to detect and correct frictional heat occurring during the measurement. Frictional heating might also initiate the curing reaction for rubbers equipped with curatives. Consequently, the upper part of the measurement slit is attached to the movable mold half to enable the demolding of the rubber compound. The moveable half comprises of a cylindrical shape and a hydraulic plunger, which is able to (1) measure the actual flow rate (corresponding with the shear rate in the slit) via a displacement transducer and (2) allows the application of counter-pressure to enable the evaluation of the pressure dependency of shear viscosity. The demolding of the rubber compound in the movable half is enabled by angular sliders which compose the cylindrical cavity. As first results obtained with this new measurement concept, shear viscosity curves of a NBR compound filled with carbon black in configuration with and without curatives are presented and compared to conventional measurements on a capillary rheometer.
    Original languageGerman
    Number of pages5
    Publication statusPublished - Jul 2016
    Event32nd International Conference of the Polymer Processing Society - Centre de Congres, Lyon, France
    Duration: 25 Jul 201629 Jul 2016
    Conference number: 32


    Conference32nd International Conference of the Polymer Processing Society
    Abbreviated titlePPS
    Internet address

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