Hydrophobic coating
Hydrophobic coating
(OP)
I'm looking for a hydrophobic coating that I can apply to polyester acoustic mesh. The ideal solution would be either a spray or dipping process. Any suggestions?
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RE: Hydrophobic coating
Works great on outdoor clothing. (There may be other products)
Harry
www.tynevalleyplastics.co.uk
RE: Hydrophobic coating
Regards
Pat
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RE: Hydrophobic coating
Yes, Scotchgard is still available and used widely. Here is their site:
http://sol
sdk,
Here is the Scotchgard product for water-repellent fabrics:
http://sol
RE: Hydrophobic coating
Same/similar stuff...
www.tynevalleyplastics.co.uk
RE: Hydrophobic coating
Checkout waterproofers under products.
http://www.thompsonswaterseal.com/
RE: Hydrophobic coating
Silicone oil or grease, applied directly, might work as well as, or better than, some of the other materials. Check the Dow website, they may even be willing to send you a sample jar.
RE: Hydrophobic coating
You will need:
1 spray bottle like you use to spray plants
2 100 ml solvent (I used hexane or heptane)
3 5ml of octadecyl trichlorosilane (or other long hydrocarbon chain organosilane)
Mix 2 and 3 in container 1. Spray onto fabric. Allow to dry.
We were able to achieve outstanding hydrophobicity e.g. on a polyester jacket. You could make a pool of water inches deep and it would just sit there for hours not wetting the jacket at all.
The easier path is, as suggested, to buy some shoe water repellent from The Show Locker or similar.
Chris DeArmitt PhD FRSC CChem
www.phantomplastics.com
Consultant to the plastics industry
RE: Hydrophobic coating
RE: Hydrophobic coating
PEG trimethoxy silane available as Dynasilan 4144 from Evomik Degussa. That is just being made obsolete and replaced with an almost identical product which is not yet listed in their literature.
For product info download this, then call them and ask what the replacement is called. I am sure you can get a sample. Momentive have a similar product too.
ht
Like all organosilanes you need to hydrolyse off the methyl groups at which point it will polymerise to give a nice biocompatible coating on your fabric.
Chris DeArmitt PhD FRSC CChem
www.phantomplastics.com
Consultant to the plastics industry
RE: Hydrophobic coating
RE: Hydrophobic coating
Thanks mate. I've made some nice materials in my time and still doing it too. The millions are slow in arriving but there is hope yet! With a growing family it would come in handy.
Chris DeArmitt PhD FRSC CChem
www.phantomplastics.com
Consultant to the plastics industry
RE: Hydrophobic coating
Regards
Pat
See FAQ731-376: Eng-Tips.com Forum Policies for tips on use of eng-tips by professional engineers &
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for site rules
RE: Hydrophobic coating
I used a can of spray paint and some hydrophobic silica, e.g. from Cabot or Degussa. You spray the paint onto the surface you want to coat, then while the paint is still wet, you dip it into the silica. The silica sticks in as the paint dries and you get an extremely good Lotus-Effect surface. You can shoot a hard jet of water at it and it still won't wet at all. Or you can play with a drop of water on it. The water will roll around with virtually no resistance so it's really hard to keep it on the surface.
I need to add that the PEG surface I mentioned will be biocompatible but definitely not hydrophobic. PEG is water-soluble and the reasons it's so biocompatible is that it forms a surface of solubilized PEG brushes composed mainly of water.
Chris DeArmitt PhD FRSC CChem
www.phantomplastics.com
Consultant to the plastics industry
RE: Hydrophobic coating
I can see the consumer issues with your hydrophobic spray...one idiot with a lit cigarette...but it still sounds like something I'd like to try unless you recommend not doing it. I've got a lot of lightweight raingear/snowgear/footwear I've thrown away when the "DWR" craps out, and having a real hydrophobic finish that could be reapplied would be worth the effort. I've tried just about every name-brand spray/wash, and they all generally crap out within a few hours of wear, or less.
Any suggestions for a source for the organosilanes, stateside? The MSDS lists water as a reactant, presumably you spray onto a fully dry surface and avoid getting anything wet until the chemical has dried/cured?
RE: Hydrophobic coating
I applied the coating I mentioned to a red Tenson brand jacket that we bought cheap used from a charity store. We also applied it to an umbrella. The water repellence on the umbrella was incredibly. The crops bounced off so well that you spray people for yards around.
The secret is that the trichlorisilanes are very reactive so they bond chemically to the fabric (that's not marketing speak, I am 1. a PhD chemist and 2. not trying to sell you anything).
The easiest source for the silanes for testing is www.sigmaaldrich.com, that's where I got mine. Commercially, good sources are Momentive, Evonik, Dow Corning and Wacker (contact me if you want contact names to friends who work there and are technical experts).
The hydrocarbon silane is what I used.
Trichlorododecylsilane
http://
I searched and see this fluoro version which will cost more but give an even more hydrophobic and oleophobic coating.
Trichloro(3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluorooctyl)silane
http:
Chris DeArmitt PhD FRSC CChem
www.phantomplastics.com
Consultant to the plastics industry
RE: Hydrophobic coating
http://www.halik.biz/hl-hydrophobic-paint
RE: Hydrophobic coating
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http://www