Static dissipative coating on Lexan
Static dissipative coating on Lexan
(OP)
I have an application for acrylic sheet about 60 cm x 60 cm (2'x2'). But I need to control static charge buildup.
I have seen clear plastics with some kind of transparent coating that they claim to be static dissipative. What kind of coatings do they put on?
Other ways to mitigate static charge?
Thanks.
I have seen clear plastics with some kind of transparent coating that they claim to be static dissipative. What kind of coatings do they put on?
Other ways to mitigate static charge?
Thanks.





RE: Static dissipative coating on Lexan
RE: Static dissipative coating on Lexan
1) Waxy or oily film cannot be used. Outgassing is a concern. It goes to space environment.
2) The harder formulation may work. What is available? conductive epoxy will not work. I have seen advertisements of some conductive layers that can be put on any plastic. What are they? Some are a few angstoms thick. They must be vapor deposits. some are microns thick. I have no idea what they might be.
3) Regarding the product that can be added to parent resin, this would be the ideal solution. Do they make acrylic sheets with this thing added so that I can buy a sheet off the shelf?
Thanks.
RE: Static dissipative coating on Lexan
RE: Static dissipative coating on Lexan
Do you need the material to be clear? LNP (part of Sabic, formerly GE) and RTP both make compounds that may meet your needs, but I don't know if they are available in clear.
Not much definitive information other than a couple places to ask, I realize. You can get sample plaques from LNP, if not both, if you need to do some testing.
RE: Static dissipative coating on Lexan
There is not any memory with less satisfaction than the memory of some temptation we resisted.
- James Branch Cabell
RE: Static dissipative coating on Lexan
Of course this only solves the charge separation between the plastic and the conductive structure. The charge is still on the spacecraft.
RE: Static dissipative coating on Lexan
Contact DSM, Sabic and RTP. They are the main players in this field. You will then need to find someone to produce sheet or parts from the resin. This will be a very costly exercise. Alternatively you could ask the three compounders if they sell compound to a sheet producer
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RE: Static dissipative coating on Lexan
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RE: Static dissipative coating on Lexan
http://www.hcstarck.de/index.php?page_id=961
RE: Static dissipative coating on Lexan
Outgassing, yes, and evaporation/oxidation of the gooey types of a-stats precludes those, and the salt-based and thiol-based resin coatings require atmoshperic moisture to stay conductive. The thin metallic coatings will work, but will usually be degraded over time by atomic oxygen at LEO - there is a NASA study/report on coatings, especially thin vapor and electro-deposits on various substrates, that is based on retrieval of a spacecraft that was purpose-built and launched to look at degradation, can't remember the name of it now...but it will give you a very good idea of the rate of degradation.
If you are operating higher up, e.g. GEO, the degradation is typically a lot slower. Ask some of the solar panel manufacturers what they use (e.g. entechsolar.com, or look at design details for the space station solar arrays, since that should be public-domain info.), static dissipation on solar arrays is a big issue, since arcing across the element contact grids due to static charge buildup is one of the main degradation mechanisms for those beasties. Last I'd heard, the predicted lifetime for a solar array in GEO was 15 years before output degraded to 50% of initial power.
A lot of work has been done on amorphous diamond coatings, which have some intrinsic conductivity. I think those coatings can be tweaked to increase the graphite composition, which can help make the coating more conductive. Dunno what the status (commercial availability) of the coatings is, it was a research project for a colleague back 10+ years ago, at a job I long since left behind...
The ss fiber that Pat mentions is one of the more bullet-proof additives to resins that I was thinking of, but even though the material is "clear", the optical properties of the part can be affected (e.g. may blur, distort or cause asterism in lenses).
RE: Static dissipative coating on Lexan
There is not any memory with less satisfaction than the memory of some temptation we resisted.
- James Branch Cabell
RE: Static dissipative coating on Lexan
I think we will most likely take the approach of tin oxide coating that bonds chemically to polycarbonate substrate. It's available off the shelf.
By the way, my use of "space environment" was misleading. My apology. I didn't mean the vacuum space, but the space shuttle indoor environment. It doesn't see atomic oxygen or other high energy radiation.
It was a good learning process. Thank you all.