can anyone talk about heat shrink properties?
Because biaxially oriented PET film is stretched, the PET molecules are under tension. Therefore they will try to shrink back to their original form when heated. This is mostly prevented by the crystallinity of the film from the "heat setting" step in manufacturing, but some residual tendency to shrink does remain. Levels of a couple percent of shrinkage can occur at high temperatures. How much the film will shrink at which temperature depends greatly on the grade of film chosen and what properties the grade is optimized for. (Magnetic tape base will be different than food packaging material, for instance.) Cynthia Bennett 20:54, 7 November 2005 (UTC)