Is the difference between these two polyimide tapes i'm not seeing?

[Andrew LB]

So i've been looking to get some Kapton tape for various projects and came across two tapes from the same company on Digikey which what appears to be identical specifications except that the "Polyimide masking tape" is a little stretchier and can handle 500v less. There are no trademark royalties being sent to Dupont for using Kapton name i'd imagine.

Perhaps one of you have used both of these products and can give your perspective. $9 vs $23 for the same size is pretty substantial.

Data sheets:
https://bertech.com/wp-content/uploads/2019/08/1-Mil-High-Temperature-Masking-Tape-Datasheet-PPT.pdf
https://bertech.com/wp-content/uploads/2021/04/1-Mil-Kapton-Tape-Datasheet-KPT.pdf

Only other thing i could think of is maybe one tape has crappy adhesive

[BrokenYugo]

According to the linked datasheets one is made from genuine DuPont Kapton, the other is a generic product. Practically speaking they're probably identical.

[Berni]

Well the glue holds down to near absolute zero temperatures, this might be important enough for someone to justify the price difference. Or there might be a blueprint for some military device designed 40 years ago that calls for using that exact partnumber of tape and using something else would require going trough certification for it.

Where you have to be careful of is buying the stuff from china. I seen tape that looks just like kapton and was sold online as being kapton. Yet when you hit it with a hot air station the stuff would warp and curl up. Looks like it was just yellow colored regular tape.

[BrokenYugo]

Yeah, the Chinese mystery stuff is the real gamble, even if the plastic is a polyimide kapton clone the adhesive may not be good hi temp silicone.

[jeremy]

My experience between using generic stuff and the real stuff has been:

- adhesive is thicker on the real tape
- adhesive is much stickier and holds at more extreme temperature ranges

For any soldering work, I always use the real stuff. If it’s just sticking things down/together while I am messing around, it usually doesn’t matter.

I’ve never come across any generic stuff which has close to the adhesive performance of the real Kapton tape. I have never really noticed a difference in the polyimide itself.

[wraper]

I’ve never come across any generic stuff which has close to the adhesive performance of the real Kapton tape. I have never really noticed a difference in the polyimide itself.

Adhesive has nothing to do with "Kapton" trademark which is allowed to be used only for polyamide tape produced by Dupont. For example 3M is by no means a crappy manufacturer but they are not allowed to call their own tape as Kapton.

- adhesive is thicker on the real tape
- adhesive is much stickier and holds at more extreme temperature ranges

Both tapes are from the same company. They probably use the same adhesive which has nothing to do with Dupont.

[wraper]

Well the glue holds down to near absolute zero temperatures, this might be important enough for someone to justify the price difference. Or there might be a blueprint for some military device designed 40 years ago that calls for using that exact partnumber of tape and using something else would require going trough certification for it.

Where you have to be careful of is buying the stuff from china. I seen tape that looks just like kapton and was sold online as being kapton. Yet when you hit it with a hot air station the stuff would warp and curl up. Looks like it was just yellow colored regular tape.

Both tapes have the same temperature range if you look into datasheet.

[jeremy]

3M does call their tape Kapton: https://au.mouser.com/datasheet/2/1/Polyimide_Film_Tape_5413_TDS-349364.pdf

And yes, I should have been clearer. I meant tape that was specifically branded as Kapton. I realize that this isn’t associated with the adhesive, but my experience has been that any genuine Kapton tape has had really good adhesive.

[wraper]

3M does call their tape Kapton: https://au.mouser.com/datasheet/2/1/Polyimide_Film_Tape_5413_TDS-349364.pdf

And yes, I should have been clearer. I meant tape that was specifically branded as Kapton. I realize that this isn’t associated with the adhesive, but my experience has been that any genuine Kapton tape has had really good adhesive.

Particular tape uses a film produced by Dupont, therefore the name. 3M has plenty of "non Kapton" polyamide tapes. https://multimedia.3m.com/mws/media/1024105O/3m-polyimide-tapes-8997-and-8998.pdf