The EN ISO 2555 standard developed by the International Standards Organization (ISO) defines a test method for determining the apparent viscosity of liquid resins using a single-cylinder type rotary viscometer. This test method is used for viscosity measurements in the range of 0,02 Pas to 60 000 Pas. This standard applies to both Newtonian and non-Newtonian fluids, and the measured apparent viscosity depends on the velocity gradient to which the fluids are subjected during measurement.
For the purposes of this international standard, the single-cylinder type rotary viscometer defines the device that determines the viscosity by measuring the torque acting on the surface of a rotating cylinder or disc in a laminar flow state at constant angular velocity. A shaft is a cylindrical or disk-shaped rotationally symmetrical object attached to a vertically rotating shaft. Apparent viscosity, on the other hand, refers to the viscosity of liquids determined from the torque measured using a predetermined calibration table.
For non-Newtonian fluids, the apparent viscosity depends on the shear rate. In these types of viscometers, the velocity gradient is not the same for every point of the spindle. Thus, for a non-Newtonian fluid, the result is not true viscosity at a strictly known velocity gradient and is thus conventionally called apparent viscosity.
A rotary viscometer consists of a spindle, a torque measuring device and a spring, and there are three types of rotary viscometers according to the spindle differences:
Single-cylinder type rotary viscometers measure viscosity under unsteady shear rate. Coaxial cylinder type and cone plate type instruments measure viscosity under constant shear rate.
When using a single cylinder type instrument, the measured viscosity is relative to the measuring conditions. It is therefore intended to specify conditions for viscosity measurements.
Among the numerous tests, measurements, analyses, and evaluations our organization provides for businesses in various sectors, we also offer testing services for determining the apparent viscosity of resins in liquid form, emulsions, or dispersions using a single-cylinder rotary viscometer, in accordance with the EN ISO 2555 standard, thanks to our trained and expert staff and advanced technological equipment.
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