Kapton film is a brand name for Polyimide which is owned by Dupont. It is a non-thermoplastic polyimide film.
It has a dark yellow color and has an extremely high working temperature. The temperature range it can work within is -260C to +400c. This makes the film extremely versatile.
Kapton dos not have a melting point and has a low coefficient of linear expansion value. This would typically be 20 parts per mm / C. This is based on test valued of -14 to +38C.
The film is not heat seal able but can be bonded to other surfaces which have a specially prepared surface.
Examples of industries the film is used in are within mechanical and electronic parts. Kapton has been specified on components that are used within space exploration. More down to earth requirements are applications such as pressure sensitive tape or fibre optic cable.
Automotive diaphragm sensors and manifolds are examples of other uses it can be used for. It also lends it self well to being used as a non stick heat barrier for the the production of PTFE belts.
These belts require hot platens that be able to thermally bond two layer of PTFE coated glass cloth together. Kapton is ideal to use as a barrier between the hot aluminum platen and the PTFE as it protects PTFE from damage.
The polyimide film is made by casting. Casting means pouring a semi liquid solution on to a high gloss surface then curing. Once cured the thin layer (film) is then carefully peeled away and batched off in to a roll.
It is possible to make self adhesive tapes from the film by preparing a surface with a chemical etch. An adhesive is applied by bonding to the etched surface and supplied in a slit roll form.