GB/T 39693.8-2022 is the eighth part of the series of standards for the determination of the Hardness of vulcanized rubber or thermal plasticity rubber, for the determination of the apparent hardness of rubber rollers. The standard specifies the scope of application, based on Zhao's Hardness (P & J) method, specifies the equipment, sample requirements, test procedures and result calculation in detail, specifies the test environment, loading conditions and other key elements, provides a unified technical standard for the scientific and accurate determination of the Hardness of rubber rollers, and helps to control the mass and performance of rubber rollers.