"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?

Is Mylar the gold standard? How safe are coins in Mylar? Which commercial
brand flips are made from Mylar?

-mazorj, now nervously eying his enflipped hoard