Apparatus for fast determination of the rheological properties of thermoplastics

Apparatus for the rapid determination of the rheological properties of a thermoplastic, comprising:

• a control and monitoring unit (1)
• a cylinder (2) intended to receive a determined measured quantity of the thermoplastic to be evaluated, and equipped with a thermostated jacketing (4) for the thermal conditioning, during at least 300 seconds and at a predetermined temperature, of the measured quantity of thermoplastic to be evaluated
• a plunger (3) capable of sliding in the cylinder (2) so as to be applied to the measured quantity of thermoplastic
• an exchanger system (5) enabling the cylinder to be equipped with a capillary die (6) suitable for the rheological measurement to be carried out a stepping-control motor (7) ensuring a monitored travel of the plunger (3) in the cylinder (2) to expel the thermoplastic through the capillary die (6), and
• a force-sensor (9) arranged between the motor (7) and the plunger (3), yielding a signal as a function of the force applied to the plunger (3), characterized in that said apparatus additionally comprises an electronic microprocessor system monitoring the stepping-control motor (7) so that at the end of the thermal conditioning the plunger (3) is situated at a distance from the capillary die (6) which permits the measurement to be carried out and acts over a period of time ranging from 10 to 180 seconds on the measured quantity of thermoplastic to be evaluated in accordance with a parameter of speed of travel or of applied force specified by the type of rheological measurement to be carried out.