Polyimide film PIN is a kind of heat resistant film possessing excellent physical, chemical, and electrical properties, which performs successfully in the wide range of temperature as low as -452 oF (-269℃) and as high as +500 oF (+260℃) and can be exposed at +752 oF (400℃) in short time. Besides, it is of atomic radiation resistant. Polyimide film is currently the macromolecular compound with the best combined properties and the highest heat resistant. PIN type have higher modulus and lower CTE than PIF type.