Design a PCB using Kapton film
Don't do that.


The kapton tape you linked to has adhesive on one side, which will interfere with whatever you try to do with it.
Kapton is available in much more suitable forms, for example these 24 x 24 inch sheets. 
Kapton is one of the most common materials used as a substrate for flexible printed circuits. You can simply call your favorite flexible circuit fabricator and have them make whatever circuit you want from your gerbers. 
If you insist on making it yourself, you can buy Kapton pre-clad with copper. Most likely you can process this with the same photoresists and etchants used by hobbyists for rigid PCBs.
You probably want some kind of higher-resistance material you can pattern on the kapton to make your heater element. Unfortunately I don't know what your options are here, particularly for materials that can stand up to flexing.