[Nhcoll-l] Potential problem with older PE jar lid liners

Wed Aug 1 11:34:24 EDT 2012

According to the Product Data Sheet from TriSeal, the seal mentioned by
Jean-Marc, F-217 PE Seal, is a three-ply co-extruded liner consisting of a
foamed Low Density Polyethylene (LDPE) core sandwiched between two layers
of solid Low Density Polyethylene (
http://tri-seal.tekni-plex.com/sites/default/files/tds_tri-seal_f-217_-_rev5.pdf
 ).  This is different from the liner described by Paul as made from
polyethylene foam.  The presence of the solid LDPE layer adjacent to the
contents will greatly change properties of the liner such as extractability
of additives, strength, resistance to tear when cap is twisted on,
sealability, etc .  We may be discussing different products, not just
different batches of the same product.  This demonstrates the need for
extreme precision when describing and ordering products.  Product
differences, especially if these include structural differences, are
probably more significant than batch differences.

My experience during investigations of adhesive and adhesive tapes has been
that seldom are there significant batch differences in products from large
primary manufacturers.  After all these manufacturers are supplying
products to many secondary converters who rely on and demand that
properties do not change.  Therefore, the primary manufactures tend to be
very careful to maintain properties.  Also, because manufacturing processes
usually are quite delicate processes with complicated interactions of
sub-processes, it is usually quite difficult and expensive to change the
manufacturing process, including the raw materials used to make the
product.  Usually when this is done, a new product is produced, usually
with a new product number or process number, new properties are published,
and the new product is described as a substitute or replacement for the
old.  This is not the case with secondary converters who assemble various
manufacturer's products into a finished product.  Here the demand on the
converter is to produce a final product with consumer defined properties.
The converter tends use whatever is available and economically advantageous
to reach that goal.  Usually the customer does not care what is used to
make his product, just that the product does the job desired in his
application.  Since the converters product still does the same job, his
product name probably does not change, even though the constituents may
have.  A common occurrence of this is the adhesive on self-adhesive
consumer (not technical) products.

I do not know about Paul's liners but TriSeal F-217 mentioned by Jean-Marc
is a technical product, with very tight specifications (and approvals) from
Food and Drug regulators, certainly for constituent polymers and additives,
and perhaps for performance factors such a sealing ability.  This approval
probably disappears if the product composition or structure changes.
Therefore we can expect uniform batches.  Unfortunately it is always
important to keep in mind that the shelf life expected by the manufacturer
for his products may be much shorter than what we want.  For example,
TriSeal may only expect (and guarantee?) their liners to last for a few
years in a consumer product like cosmetics or drugs (which always have
expiry dates), and not the decades we want.

All this considered, it must be stated that 20 years of successful
application of the F-217 seal at CMN is a good evidence that this product
is performing well in a pretty harsh application.  I wonder if TriSeal
would be surprised to hear this?

This old email address will no longer be supported by our department:
scott_williams at pch.gc.ca

Please change to my current email address for future contact:
Scott.williams at pch.gc.ca

R. Scott Williams
Senior Conservation Scientist (Chemist), Canadian Conservation Institute
1030 Innes Road, Ottawa, Ontario, Canada K1A 0M5
tel: (613) 998-3721
fax: (613) 998-4721
email: scott.williams at pch.gc.ca

From:	Jean-Marc Gagnon <JGagnon at mus-nature.ca>
To:	"'Paul Callomon'" <callomon at ansp.org>, "NH-COLL listserv
            (nhcoll-l at mailman.yale.edu)" <nhcoll-l at mailman.yale.edu>
Date:	2012-08-01 08:14 AM
Subject:	Re: [Nhcoll-l] Potential problem with older PE jar lid liners
Sent by:	nhcoll-l-bounces at mailman.yale.edu

Paul,

At the Canadian Museum of Nature, we have been using F217 PE Seals for a
good 20 years and have not observed deterioration. This is not to say that
we have checked all lids with such gaskets installed since that time, but
we have had the opportunity to open quite a few.

As Stott Williams indicated, there may certainly be differences between
batches, as it’s been for instance observed for batches of Ethafoam and
other closed-cell polyethylene products.

While it is still hard to predict the long-term durability of PE seal, the
use of a good sealing tape around the lid can certainly serve to at least
partly mitigate this problem and insure the preservation of the collection
specimens (Steigerwald, Michele and Sylvie Laframboise, 1996. Tape
application: a jar sealing method for reducing ethanol evaporation in
fluid-preserved collections. Collection Forum 12(2): 45-53).

Jean-Marc

Jean-Marc Gagnon, Ph.D.
Past President (2012-2014) of the Society for the Preservation of Natural
History Collections (www.spnhc.org)

Curator / Conservateur des collections
Invertebrate Collections / Collections des invertébrés
Canadian Museum of Nature / Musée canadien de la nature
P.O. Box 3443, Stn "D" / C.P. 3443, Succ. D
Ottawa, ON Canada K1P 6P4
T: 613-364-4066 / F: 613-364-4027
E/C: jmgagnon at mus-nature.ca
http://www.nature.ca

From: nhcoll-l-bounces at mailman.yale.edu [
mailto:nhcoll-l-bounces at mailman.yale.edu] On Behalf Of Paul Callomon
Sent: July-30-12 3:56 PM
To: NH-COLL listserv (nhcoll-l at mailman.yale.edu)
Subject: [Nhcoll-l] Potential problem with older PE jar lid liners

Colleagues,

I have today found a severely deteriorated jar lid liner in our alcohol
collection. The liner is made from polyethylene foam. It was sold to us in
1999 and installed in 2000. The material has failed completely, with
crazing and cracking of the surface and tearing along the compression face.
The foam has become weak and powdery in places. The jar was filled with 70%
ethanol.

The manufacturers have suggested that the use of this liner for long-term
storage of alcohol is responsible for the deterioration. If this is true,
the implications for our collection – we have about 20,000 bottles that use
these liners – are potentially serious.

Does anyone have experience with this problem? Are Teflon liners a better
alternative?

Paul Callomon
Collections Manager in Malacology, Invertebrate Paleontology and General
Invertebrates
The Academy of Natural Sciences of Drexel University
1900 Benjamin Franklin Parkway
Philadelphia, PA  19103
callomon at ansp.org
Tel. 215-405-5096
ansp.org
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