It might be Kapton tape, although the Kapton I've used was orange-colored. We used to use it on electronic connectors that were being overmolded, to keep the molten plastic from flowing where it wasn't wanted.
Where I worked we used Kapton in vacuum chambers where satellite equipment was being toasted by quartz lamps. It's pretty good stuff. For our applications it not only had to resist heat but also not outgass in vacuum. It's a yellow brown in color though.
Another brand in use at the same facility that's blue like the sample you posted the URL to is sold by this outfit:
They appear to be polyester tape with silicone adhesive, so nothing new. I suppose they soften along with the polyester powder at the ~400°F cure temperature, but the silicone adhesive keeps them from sticking permanently. I don't think I've seen the translucent green & blue colors before.
Best regards, Spehro Pefhany
"it's the network..." "The Journey is the reward"
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Methinks that this is teflon tape, which is hi-temp stuff until it burns and outgasses some nasty stuff. Very slippery stuff. Almost feels oily, and you have to grab it just right to handle it. Trying to recall who makes this kind of tape.... Scotch? Permatex? Permacell?
Look over the class 1 masking tapes - the 2693 is a good start. There are several to check - and make price cut based on volume of total world market. Maybe the 2380 in class II. (Cheaper by class I bet)
Then searching for powercoat :
3M? Composite Bonding Tape 8905, 10 in x 72 yd, 4 per case [click to enlarge] Clean removing high temperature silicone adhesive and tough non-slivering polyester backing makes this tape a popular choice for powder coat paint masking. 6.6 mil (0.17 mm) total thickness.