This standard specifies a method for determining the viscosity of a rubber paste using a rotational viscometer. The viscosity is measured using the shear force generated by the rotor in the rubber paste by immersing the rotor of the rotational viscometer in the rubber paste and swirling/spinning it at a specified rate of rotation. The standard describes in detail the structure and working principle of the rotational viscometer, including a motor drive shaft and devices for connecting different rotors, as well as provisions for the depth of immersion of the rotor. In the measurement process, the viscosity of the rubber paste is determined by measurement of the equilibrated state of the rotor torque. This standard is suitable for the rubber industry's need for accurate determination of slurry viscosity, ensuring Reliability and comparability of measurement results.