Plastic Ain’t Forever..... Is It?

Doing some winter work on my old boat. While replacing the clear plastic windscreen for the second time in twenty years it occurs to me that plastic ain’t forever. Granted, my boats windscreen is not pampered like my slabs are. But TPG plastic is a relatively new thing. Is there an expected lifespan for TPG slabs?

 

Log in or Sign up to hide this ad.

Plastic is Plastic...
Lifespan? A few thousand years!

Consider the lifespan of these popular plastic products:

• Plastic Water Bottle - 450 years
• Disposable Diapers - 500 years
• Plastic 6-Pack Collar - 450 Years
• Extruded Polystyrene Foam - over 5,000 years

 

Really? It won’t start to yellow as it ages?

 

It is only forever when it is floating in the middle of the Pacific Ocean.

 

That will happen if you are a smoker

 

Many plastics exposed to the sun will "fog" over time.
Look at the headlights on cars 5 or more years old.
The plastic reacts with the UV light from the sun.

I assume you don't leave your slabs out in the sun

 

In the future we will have ancient coin collectors and ancient slab collectors

 

The future is now.

There are quite a few people who research and collect early or rare slab types. There's even a book about it (although it is quite old).

 

The plastic dumped in the oceans degrades and turns into minute particles ingested by marine life poisoning them.
Its mass pollution.

The plastic used by the slabbing companies is usually some kind of trade secret, but no doubt it's as stable and inert as their R&D departments can make it, and should do no harm to the coins for the short or medium term.
But frankly, we simply don't know how any kind of plastic will behave in the long term - plastic hasn't been invented for long enough.

They can do all the artificial ageing tests they like, but the only true test of how a material ages is to wait around for several centuries and see what actually happens.

We know some plastics degrade very quickly, and destroy any metallic objects embedded in them as they degrade (the plasticized PVC you often find in cheap coin albums is an excellent example). We also know that plastics are not eternal, and slabs certainly will not last as long as the gold, silver and copper coins they are purporting to protect.

 

UV breaks the polymer chains in most plastics over time, if left exposed to sunlight a plastic bag or straw will decompose to dust, not sure about the exact timeframe though.

 

Has anyone left a slab out on the window sill with round the clock sun exposure?

I'd be interested to see the sun's effects on NGC / PCGS slabs, and the effects on the coin (by the exposed plastic onto the coin, and by the sun onto the coin). I also understand that the plastic inserts to touch and hold the coins are inert, but maybe the outer plastic may affect it.

 

I'll let you know if I live 1000 years. I'm sure I'll be encased in a different kind of slab without attribution.

 

Many plastics yellow over time with UV exposure, and can turn more brittle as well. But I think the fogging you see on headlights is from abrasion -- hitting dust, insects, and gravel bits as you're driving. Look closely at fogged headlights, and you can see the scratches. You can polish them out, too.

I think we've all seen scratched slabs, and I know there are products available to polish them. I've never seen a yellowed slab, but I've also never met anyone who's left a slab out in the sun for several years. Even if the plastic and the coin held up, the label certainly wouldn't fare too well.

 

As an aside, Here in NE a man by the name of Harold Warp invented and patented Flex-O-Glass which was the precursor to Plexiglas. It was intended to be used on his chicken coops. The back story is that I talked with a couple of farmers in the area who were very mad about him putting a patent on the invention as they claimed they were developing it with him and he quickly put the patent on the invention, thus reaping the rewards. I believe it was used on jet fighter windshields at the time.

 

I think that due to the types of storage we see and the lengths people go to preserve their coins you will see very few ill effects of yellowing on slabs.

 

Now that it’s been discussed, yes it does make sense that UV causes the plastic breakdown that I was thinking of..... Now I wish I had a cracked out/throw away slab. I would like to lay it in the South Carolina summer sun and see how long it takes to yellow or break down.

 

That may be, but a lot of it has to do with road dust and debris scratching the lens. That's why auto supply stores sell abrasive products to clear them.

 

Most kits sold to restore headlights use a solvent to remove the thin layer of UV-damaged polycarbonate from the surface of the lens. Then a polish is used to restore the lens to its almost original finish.

 

HA! There is no "round-the-clock" sun exposure unless you're on space lab