WARNING—Personnel using this part of GB/T 14797 should be familiar with the operating procedures of formal laboratories. This section does not intend to address all security issues that may arise from the use of this section. Users should formulate corresponding safety and health rules and ensure compliance with relevant national regulations. This part of GB/T 14797 specifies the method for determining the viscosity of vulcanized natural rubber latex with an L-type rotational viscometer. This part applies to the determination of the viscosity of vulcanized natural latex, and also to the determination of the apparent viscosity of natural latex and special latex prepared from natural latex.