Transparent plastics that are opaque to longwave UV light? 1

[DigitalHorizons]

Hi, I am new to the forums, I am working on a project that would require a plastic similar to lexan or plexiglass that's transparent at visible wavelengths but opaque or nearly opaque at longwave UV wavelengths. Is there such a plastic on the market?

 

[patprimmer]

Yes

Regards
Pat
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[Demon3]

I would recommend transparent ABS, BASF sell it under the name Terlux. The reason being that it's full of impact modifier particles that have the same refractive index as the matrix so it's transparent to visible light. It will not however be transparent to UV light for two reasons.

1. It contains polybutadiene which has double bonds in it which should adsorb UV

2. The rubber particles are the right size to scatter UV and the refractive index in the UV range is different than to visible light so the particles and matrix will have a mismatch (strong scattering)

In addition to that it's an easy matter to add some UV adsorber

The same as above should hold true for some other rubber particle impact modified polymers like PMMA.

All the best,

Chris

Chris DeArmitt
Plastic & Additives Webinars
Training the Fortune 500 since 2003

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[DigitalHorizons]

Thanks, Chris, Pat. How expensive is transparent ABS compared to say transparent cast acrylic? Is the clarity the same? Can a UV absorber be added to acrylic? What are some common UV absorbers in use?

 

[patprimmer]

ABS and acrylic should at least be in the same ballpark, but my knowledge of comparative costing is fairly out of date and it can also vary quite a lot by region.

Acrylic it the clearest material you will get and is considerably clearer than clear ABS.

It can be treated with UV absorbers. A master batch supplier should be able to provide data on transmission or absorption curves for various UV absorbers. I have data somewhere for natural acrylic. Ciba used to be the company of repute in the UV absorber field.



Regards
Pat
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[DigitalHorizons]

Ok, thanks, cause I need the most transparent plastic I can get with this, I know most plastics are somewhat opaque atleast to shorwave UV normally but I need something that will be opaque to longwave UV like you would have from blacklights, is Ciba still in business?

 

[patprimmer]

http://en.wikipedia.org/wiki/Ciba_Specialty_Chemicals

It took me a whole 3 seconds to find this on google.

Regards
Pat
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[Pud]

This might be useful:

http://www.topas.com/index/tech-services/tech-service-performance-data/techinfo_uv_transmission.htm

H

http://www.tynevalleyplastics.co.uk

Why be happy when you can be normal?

 

[IRstuff]

Generally, "visible" is incompatible with "rejecting" UVA, since they're basically right next to each other in the spectrum, at least, for low cost.

If money is no object, then high quality filters can be developed and used.

TTFN

FAQ731-376
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[DigitalHorizons]

Thanks for the help, everyone. Looks like I got my work cut out for me if I'm gonna be able to block UVA while keeping visible transparency, the UV filters seem like a great choice but price and patent issues might be a problem.

 

[patprimmer]

I don't see a patent issue. UV blockers or absorbers have been used for decades to block out or protect from UV light. They have also been used in Acrylic sheet since at least the 70s for Museum grade Perspex to protect items on display from damage due to UV light.

Regards
Pat
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[DigitalHorizons]

That's good to know, I just found a truview acrylic sheet with UV absobtion for paintings online, hopefully it has some UVA blocking ability, will be contacting the company soon.