Polyethylene(?) fluorescent dye quenching

[btrueblood]

I think I know the answer to this, but want to ask.

Lots of fleece clothing on the market these days, it's cheap and warm. Makes good hunting clothing. But most of it also has optical brighteners or UV dyes (OBA's) added, and I assume it's added to the melt prior to being extruded to fibers. The OBA's would tend to counteract the purpose of camoflage for hunting, tending to make the user glow bright blue when outdoors, even in low light.

If I'm right, and the OBA is added to the melt of the poly fiber, is it possible to quench these dyes after the fact, i.e. washing in a chemical compound or application of a spray coating (durable or otherwise). I know there are products that can do this for paper fibers, but those are water-soluble and are intended to react with similarly water-soluble OBA's used in paper finishing. There are some products marketed as quenching or killing the effect of OBA's on clothing/textiles, but I wonder how effective they can be on poly fabrics.

 

[Demon3]

I have worked some on optical brighteners. I am not sure why they would be added to colored clothing as there would be no point. As you know, they absorb UV light and emit blue. That's helpful when you have white clothes with a hint of yellow because the blue light emitted masks the yellow so you make the clothes appear whiter. They would have no purpose I can imagine on colored clothes. I presume people don't hunt in white business shirts which is what the brighteners are used for.

A big problem is that a lot of detergents contain optical brighteners so you are in effect reapplying new optical brightener every time you wash your clothes even if it didn't contain brightener when purchased.

In your shoes I'd try detergents designed for use with colors as they presumably don't contain brighteners. Also buy a UV flashlight (they're cheap) and shine it on your clothes. If they glow then you have optical brightener present.

If there is brightener present then I suggest you try washing the clothes in bleach with no detergent. Bleach may well neutralize the brightener.

Chris DeArmitt PhD FRSC CChem

http://www.phantomplastics.com

Consultant to the plastics industry

 

[Pud]

btrueblood: I thought you lot (USA) had to wear bright orange/dayglo uniforms when hunting to stop you shooting each other?

One day you might even be allowed silencers in the land of the free!

(Gentle prod in the ribs from the most gun-controlled country on the planet - apart from North Korea!)

H

http://www.tynevalleyplastics.co.uk

 

[patprimmer]

OBAs convert invisible UV light and emit visible blue light.

There has to be a suitable supply of UV light and a relatively dark surroundings for them to glow noticeably, so in poor natural light there will be little UV to excite the emission.

The blue glow will be absorbed by the dyes in the outer layers which I presume are olive drab.

OBAs also absorb UV light so they act as stabilisers and are sometimes used for that purpose.

You cannot dye the PE to quench the OBA as PE won't absorb any dyes at all.



Regards
Pat
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[Compositepro]

Dyes and brighteners are almost always added after the fiber is made, often after it is woven. All hunting supply stores will carry products to remove scents and brighteners from clothing. It's a well known issue and there is plenty of money to be made selling these products. I don't know the chemistry of these products but a patent search or Google search would reveal it. Just yesterday I read the label on one of these products and there were no ingredients listed.

 

[patprimmer]

They are for nylon, polyester and acrylic, so the colour can be determined with minimum lead time to market, but certainly not for polyethylene or polypropylene as both these are impervious dyes.



Regards
Pat
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[btrueblood]

Pud is correct, and it's what made me start wondering. You'd think OBA's would be completely ineffective under heavy fir canopy, in cloudy weather...but it was surprising how well fluorescent clothes stand out in those conditions (until recently I'd never hunted in such garb).

So I took a UV LED, and shined it on my hunting clothes, and lo and behold, in the white patches of some of my camo wear, I get nice shiny blue fluorescence. But dulling the day-glo orange down a bit wouldn't be a bad thing in my mind either, if it could be done inexpensively.

CPro, yes, and the stuff (de-brightener) is very expensive. Also not sure, I fear Pat may be right, and the poly fleece (I think the stuff is polyethylene based, don't think it's polyester, but may be wrong) won't take any dye or treatment.

Thanks all, curiosity made me ask, and some google searches had me pretty confused; there's an awful lot of chemicals that apparently work as uv brighteners, and the chemistry rapidly got way over my head.

 

[IRstuff]

I thought you lot (USA) had to wear bright orange/dayglo uniforms when hunting to stop you shooting each other?"

Only when Mr. Cheney is in the area...

TTFN

FAQ731-376

 

[Demon3]

Fleeces are usually polyester, i.e. PET like the soft drink bottles.

The optical brightener probably comes from your detergent.

Chris DeArmitt PhD FRSC CChem

http://www.phantomplastics.com

Consultant to the plastics industry

 

[patprimmer]

I agree with Chris.

Wash these garments only with plain soap or dish washing or truck wash detergent.

To test if it's PET or PE, if you can cut of a few short fibres without unacceptable damage, put the sample in water with a bit of wetting agent and see if it floats or sinms. Be careful that entrapped air is not keeping it afloat.

PEs SG is somewhere in the 0.9s and PET I think from memory is about 1.3. It is certainly well over 1.

Regards
Pat
See FAQ731-376 for tips on use of eng-tips by professional engineers &

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[Demon3]

For wetting agent read dishwashing detergent.

Nice idea Pat.

Chris DeArmitt PhD FRSC CChem

http://www.phantomplastics.com

Consultant to the plastics industry

 

[Pud]

Btrueblood: Are you shooting bees? I can't think of any mammal what has UV vision capability. (Not many have colour either)

To get your dayglo stuff less vis - don't wash it - ever! (or buy one of these:

http://www.army-surplus.org.uk/product_info.php?products_id=2103

Then no-one will see you!!!

H

http://www.tynevalleyplastics.co.uk

 

[btrueblood]

Pud,

It's the bright glow in the visible region that the OBA's create that I'm worried about. Last year I had my #2 son sitting under a maple tree in the fall, you know - orange leaves? From a distance, I thought he'd blend in well even with a fluorescent orange jacket. Again, cloudy day, heavy forest cover, late fall evening, you'd think the UV incoming would be low...but he positively glowed from several hundred yards away. Or maybe I'm developing UV sensitive retins? It's probably something in the wine, better switch back to beer.

 

[lumenharold]

btrueblood - I would think that you would want other hunters to see your son in the woods. I found this ESPN article interesting regarding what deer see:

http://sports.espn.go.com/outdoors/general/news/story?page=c_fea_QDMA_what_deer_see

Seems like sit still, be quiet and hunt in the daylight is the solution although not what the OP asked for.

Harold
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Dell 690, Xeon 5160 @3.00GHz, 3.25GB RAM
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http://www.lumenflow.com

 

[btrueblood]

lumen,

Let's leave the debate about day glo orange for another day.
Suffice to say, when it's mandated, we wear it.

This comment from your posted article has me and several other hunters thinking:

Deer, on the other hand, do not have a UV filter. Therefore, they see much better in the UV spectrum but lack the ability to see fine detail. This explains why deer often move their head from side to side when they encounter a hunter. Since deer lack this filter, they would be expected to see a greater difference in UV treated fabrics than humans.

 

[lumenharold]

btrueblood - not looking to ruffle feathers or for a debate. I have spent a lot of time in the woods in Michigan although I no longer hunt. Article was posted as information not to antagonize. I think it supports both sides of the discussion with regards to UV fluorescing dyes and has some good information in it.

Harold
SW2010 SP3.0 OPW2010 SP1.0 Win XP Pro 2002 SP3
Dell 690, Xeon 5160 @3.00GHz, 3.25GB RAM
nVidia Quadro FX4600

http://www.lumenflow.com

 

[btrueblood]

lumen,

No feathers ruffled...at least not yet (duck season opens soon, though).

 

[Compositepro]

This website has some interesting and relevant articles.

http://www.atsko.com/articles/clothing-care/washing-acu-army.html

The uv blocker treatments are dyes that absorb uv but not visible light, like sun screen.

Apparently polypropylene can be dyed with appropriate processes while polyethylene cannot. I'm not aware of polyethylene being commonly used in clothing.

 

[Demon3]

You can dye anything if you want to badly enough but PE and PP are hard because they have no functional groups, i.e. "handles" for the dye to grab onto.

Chris DeArmitt PhD FRSC CChem

http://www.phantomplastics.com

Consultant to the plastics industry

 

[patprimmer]

Chris

I believe that there are now some textile grades of modified PP that have dyesites embeded into them. I don't know how effective they are. I do know that a similar technique on other fibres to make them accept different dyes for differential dyeing effects where prone to saturation when all sites where ocupied and no further uptake is then possible. That is even an issue with nylons and is why nylon 6 takes more dye than 66 or especially 11 and 12 as the dysites in nylons are the functional groups.

I don't know the degree to which dyesites can be or are added to PP

Regards
Pat
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