This International Standard lays down the basic dimensions and tolerances, in millimetres, of type A and B thermal insulating sheets for plastic and rubber moulds. Thermal insulating sheets are used in applications where heat transmission between injection mould and machine platen has to be reduced. This International Standard also gives material guidelines and design requirements, and specifies the designation of the insulating sheets. The dimensions of the sheets have been chosen to match those of mould plates specified in ISO 6753-2. For type B sheets measuring 156 mm × 156 mm and larger, the diameter of the hole has been chosen to match the fitting diameter (Ø 90 mm) of locating rings.