Outdoor use of Corian with dye-sublimation - curious about UV fading period

[Robert Johnson MI]

I've read a lot about how dye-sublimation is not particularly UV stable, and that it will fade with direct UV exposure. I've read several (very old such as http://www.sawmillcreek.org/showthread.php?62086-Dye-Sublimation-of-Dupont-Corian&p=62086) threads here about Keith Outten trying dye-sublimated Corian for some outdoor applications. What I havn't been able to find are pictures or descriptions of this fading (in simulated or real lifeexposure) or looks like. Do the colors just become less vivid, ghosting, dye shifted (get fuzzier), does it disappear completely.

Any information (and especially pictures) would be very welcomed. I plan on doing my own testing and publishing my own results as I see them, but unless it fades really quickly I may not have anything to show for a long time :) My goal is to make an honest effort to inform my customers of possibilities and what to expect, the people I've spoken with so far don't expect a sign to last forever but they do want to know if its going to look extremely weathered after a couple months.

If you have any suggestions on how to improve outdoor lifetime I'd love to hear those too. I've heard mixed things about frog juice, clearjet and some other sealants so I'm going to try them out on Corian and a couple other substrates and leave them out in the weather to see what happens, and how long it takes to happen.

[Keith Outten]

Robert,

My first test involving a dye-sublimated Corian picture exposed to UV lasted about four months during the Summer. I made two identical pieces and placed one of them on the dashboard of my truck for the entire Summer, the second piece I kept on my office desk. At the end of the Summer there was no difference in the two Corian samples.

I placed a picture that was dye-sublimated onto FRP on a post facing North in the front of our office at CNU. After three months the picture was terribly faded. A Southern exposure would probably have taken less time to fade.

The problem with this kind of research is that it takes a long time to get results and the results may not be accurate unless you know the details. I have had long conversations with someone who tried to dye-sublimate Corian whose results were different than mine. I was able to determine that the reason his tests were different then mine is that he didn't use the same time and temperature that I use. Twenty minutes at 320 degrees F will allow the dye to penetrate the Corian substrate several thousandths on an inch deep. Corian has to get very soft before the dye will sublimate to any depth, the depth has everything to do with performance.
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[Rich Fennessey]

Note that glass will block various spectrums of UV depending on the type of glass. It is nearly impossible to get sunburn through your automobile windshield. This could be why your picture on the dashboard may have endured so well. According to this article, automobile glass is especially good at blocking.

http://www.smartskincare.com/skinprotection/uv-indoors.html

The best protection comes from the types of glass specially geared towards blocking UV rays, such as laminated glass and UV-blocking coated glass. Both filter out from 95 to 99% of all UV light. Neither is common in residential or commercial structures. Laminated glass, made of two layers of glass with a plastic layer in between, is used in some public buildings, such as airports and museums; it is also used for automobile windshields. UV-blocking coated glass is also used largely in special circumstances. All in all, whenever indoors, don't assume protection from the windows against UVA unless you know that special glass in installed.

[Ken Dolph]

There are two main aspects to dye sublimation:

The first is the ink itself. In the United States there is only one manufacturer regardless of the name. Their patent is still valid. Their inks have been improved over the years as to UV stability.

The second is the substrate. In most cases the substrate is polyester. Polyester is not stable in UV. Often stabilizers are added(like PABA) but they are sacrificial. They more or less slowly disappear. Then there is no protection. Polyester is sprayed on ceramic to allow for dye sublimation.

Corian is about 70% mineral and 30% clear acrylic. Acrylic is not affected by UV and it transmits very little. This will protect the dye sublimation product as the process drives the inks about .003" to .004" into the Corian.

That being said, I have not done long term full sun testing. Since I started doing it 17 years ago you would have thought I would have.

I will be interested in your tests.