In article ,
says...
Don't know the name for it, used in "oven tray liner". Takes high
temperature, does not stretch or tear and is only 0.05mm thick, highly
flexible.
Under a microscope it appears to be woven kevlar fibres squashed between
PTFE sheet. Unfortunately even puncturing with hundreds of needle holes I
cannot find a way of gluing it, even just a lap joint with no forces
involved, tension or shear.
probably same as this
http://www.theptfeshop.com/product.p...ing-tray-liner
Found in local ordinary baking products shop, quite cheap

One company I worked for used a product
they referred to as 'kapton tape'. High
temp (withstood soldering irons) and
adhesive backed.

Of course, your def. of 'high temp' might
differ from theirs.

HTH