mazorj wrote:
"Mr. Jaggers" lugburzman[at]yahoo[dot]com wrote in message
...
mazorj wrote:
"Reid Goldsborough" wrote in message
...
There are three interesting columns in this month's Numismatist
relating to previous discussions here and touching upon the issue
of truth and misinformation in numismatics. With the first, the
author of the Collector's Edge column repeats the misinformation
that soft flips cause PVC damage because "the chemical PVC is
added to make the flips more pliable" and leaches out of the
plastic onto the coins. In truth, soft flips are made of PVC, with
PVC just being another name for vinyl, which is the plastic
they're made of. PVC (polyvinyl chloride) on its own is rigid and
needs plasticizers (typically, phthalate esters) to make it soft
and pliable. It's the plasticizers that cause PVC damage. The
author also incorrectly states that hard flips don't contain PVC.
Some hard flips in fact are also made of PVC but have less
plasticizer in them and are marketed as "safety flips," safer for
coins than soft flips. Other hard flips are made of a different
plastic, polyester, frequently referred to by its brand name
Mylar. All this has been discussed here, on the Web, and in the
Numismatist and other publications many times, yet the
misinformation continues, not only by some numismatic writers but
by some coin supply dealers.

So is any PVC-based flip really "safe" for long-term storage since
they all contain some amount of plasticizers? Or should we view all
claims that imply permanent safety as marketing puffery?

I have uncirculated coins that have been in Kointainer Saflips for
thirty years without showing any signs of deterioration. But yes,
all claims of permanent safety are puffery. It's that pesky entropy
thing that'll getcha in the end.

James the Biologically Evolved

Okay, that's a good testimony to the Kointainer ones.

Entropy will win in the end for all things, but before the universe
settles down to an amorphous mass, a few other things will happen,
like all those clear sheets of supercooled liquid (a.k.a. glass)
puddling under my windows. That's going to let in the elements, which
can't be good for coin storage regardless of which brand of flips you
use.
I'll be happy if my specimens survive without visible damage long
enough for my children to appreciate what I've passed on to them. After
that, it's their problem!

It's only a matter of time until some loudmouth swings through here and goes
ad hominem on you for claiming that glass is a supercooled liquid.

Meanwhile, here's a disquisition on the topic:

http://math.ucr.edu/home/baez/physic...ass/glass.html

James the Vitreous