Thermal Characteristics

An explanation of the meaning behind and the measurement method for the main physical properties measured.

Rate of Dimensional Change

Unit %
Purpose / Details A numerical value expressing to what extent dimensions change when the film is heated. Dimensional changes greatly affect the conditions when being processed by the customer, and so this characteristic must be stable.
Measurement Method / Standards In accordance with JIS-C-2151 and ASTMDD-1204. PET film for industrial materials is often measured by heating at 150°C for 30 minutes or 190°C for 30 minutes.
Specific Measurement Method
  1. (1) The length of the sample is measured before heating.
  2. (2) The sample is suspended under load in a hot air circulating oven for the specified time and temperature.
  3. (3) After cooling to room temperature, the length of the sample is once again measured in the same area as the previous measurement.
  4. (4) Thermal shrinkage is obtained via the following calculation.
Rate of dimensional change (%) = 100 × (Lo - L) / Lo
Lo: Sample length before test, L: Sample length after test