"Kapton aka polyimide film is used in, among other things, flexible printed circuits (flexible electronics), etc.
In 3D Printer Kapton tape is used in hot end construction, to place and hold the thermistor/heating resistor in place + provides good insulation. Kapton Tape adheres so well to ABS and thereby prevents ABS parts from warping, it is commonly used by members of the RepRap community for covering the surface of a heated build platform. The adhesion is so strong that the tape may be pulled off the platform by warping of the part instead.
Kapton tape is used in many applications due to its excellent properties
High insulation, High temperature resistance ((-269 to +400 °C)), Acid and alkali-resistance, Low electrolysis, Mechanically sound, Crocking resistance, Tear-resistance"