If they mean PVC, burning it will yield the acrid smell of hydrochloric acid. Note that in general, burning plastics give off any number of noxious compounds, e.g., cyanide in nitrogen-containing polymers. A great reason not be inside a burning car or aircraft.
The main issue with plastic labels is they inevitably deteriorate in sunlight. The UV rays slowly create more points where the long molecules become cross-linked so it gradually becomes stiffer and more brittle. Unless you want to rub your labels with sunscreen every day, you have to live with this tragic reality. One thing to try is write the name on both ends of the label, so if the top breaks off, you can pull up the label and read the bottom. Also, unless this is a show garden, if the labels are mainly for your own use you can push them down so only 1/2" is sticking out of the dirt, then just pull up when you want to refresh your memory.
Getting back to your specific question, with the caveat that I'm a materials scientist and not a polymer chemist per se, my gut feeling is that pure white labels are more likely to be "virgin" as opposed to recycled plastic for a number of reasons, including the difficulty of avoiding bits of colored material in the recycle stream. At the same time, I would be surprised if recycled material would be any more or less resistant to UV damage. If there's a real polymer person in our midst I will of course defer to their insights on this problem, which has plagued gardeners since I was in grad school 50 years ago!
Bob a gloomy Zone 7 but at least it's not 4 degrees as it was at Christmas
On Monday, January 9, 2023 at 09:18:08 AM EST, Shoal Creek Succulents via pbs <pbs@lists.pacificbulbsociety.net> wrote:
Happy New Year All-
Time and again the subject of labels has been discussed. Most recently,
the longevity of vinyl labels caught my attention.
There appears to be people with a chemical background on this list.
Is there a test to confirm vinyl? I found a website that says burning
various plastics will show which material by crumble, smell, flame color,
etc.
The labels I am purchasing are supposed to be .020” virgin vinyl.
Is there a simple test to verify I am receiving material as purchased?
Thanks much!
Best regards, Lisa
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