The ISO 13636 standard specifies requirements and test methods for non-oriented polyethylene terephthalate (PET) films and sheets. The standard applies to non-oriented PET sheets involved in production, use and quality control. Non-oriented PET sheets are widely used in Encasement, labeling, electronic products and other fields. The standard includes requirements for the physical, mechanical Properties and Appearance mass of PET sheets to ensure their Stability and Reliability in different applications. In addition, the standard also specifies the test methods of PET sheets, covering the measurement of key performance indicators such as thickness, density, tensile strength, etc., to ensure that they meet industrial requirements.