[Nhcoll-l] [EXTERN] Re: [External] RE: Failure of plastic lids in ethanol collections
Dirk Neumann
d.neumann at leibniz-lib.de
Sun Mar 10 07:13:27 EDT 2024
Hi all,
if these lids are old, I suspect there might be another reason worth considering: plastics are ageing. This is a common phenomenon that can (and is) surely accelerated by UV, but there are other aspects worth considering as well.
John and Rob already mentioned that that the post common plastics found in collections are PE, PP and PVC, worth adding probably is Bakelite, the typical black screw-on lids (the older from the 1960ies and 70ies usually come with a inner cork-liner with later on was replaced with a PE insert).
Especially PVC and Bakelite are unstable over time, Bakelite because of its phenolic rings (Bakelite is a phenolic resin that results from the condensation of phenol with formaldehyde), polyvinyl chloride because it is monomers include very polar chloride. Besides the UV that attacks lids from the outside, inner vapour (especially if the storage room climate fluctuates) tend to condensate on the inside of the lid. The condensate is mostly water vapour, which, in the presence of formaldehyde gas may acidify. But also lipids and fats may play are role in the deterioration of plastics and can accelerate the process. Another reason in snap-on lids surely is the loss/deterioration of the softener that (originally) made the plastic lids more flexible and elastic. Stress cracks or embrittlement at the rims of the snap-on lids usually are a good indicator for a loss of elasticity.
If you now observe that it is always the same type of plastic lids (while the other plastic lids in the collection may still be doing fine), it would be worth assessing if these specific lids or, within a specific batch of these lids starts failling. The dates, design and jar type where these labels have been added may be a good indicator for the initial filling of the respective jars. Simon mentioned already the famous Copenhagen jars. The came with PE and PVC lids, where produced in the late 1980ies/early 1990ies, and started failing around mid 2000 in various collections simultaneously. But not all, there were some PE lids from the 1980ies that still do fine.
We compiled a lot of this and similar information in our SPNHC book on fluids preserved collections (link<https://www.universityproducts.com/best-practices-in-the-preservation-and-management.html>)
If specific lids and the lids cannot be replaced, the entire jar should be replaced. The time and long time costs (additional monitoring and handling requirements) usually are way more expensive than replacing the entire jar.
Maybe worth adding ...
With best wishes
Dirk
Am 08.03.2024 um 20:21 schrieb Lance McBrayer:
Thank you EVERYONE for the excellent information and suggestions.
These lids are old and could be part of the 'bad batch' mentioned, or they were likely exposed to some UV prior to the new facility. And yes - the light. That is a fantastic point I didn't even consider. It would have taken me months to run all this down in the literature....whew. What a relief to get your suggestions.
I'm sort of on an island at my Uni as a curator in my position so ...this is an amazing, and super helpful, community. You all ROCK !
I have a clear path forward and truly appreciate your help, guidance, and taking the time to reply.
thanks
lm
On Fri, Mar 8, 2024 at 1:18 PM Bentley, Andrew Charles <abentley at ku.edu<mailto:abentley at ku.edu>> wrote:
Hey Lance
Great info provided by both John and Rob. I would add from our experience with the same lids from Kols/O’Berk that we are not seeing systematic failures with these lids but random replacements over time. We have not noticed any greater number of failures on higher shelves but do have either LED or UV shielded fluorescent lights throughout our facility. I just undertook a full inventory of our collection to top off alcohol levels and check lids and would say that there was less than a 10-15% failure rate and it was limited almost exclusively to 8oz jar lids and mostly the unlipped variety (see below).
One thing we have noticed is a higher rate of failure with a specific type of lid that was shipped from Kols some time back (the right hand kind in the attached image that does not have a outer lip to the lid) where the lid will crack along the edge when tightened). We have now started ensuring that we get the left hand kind whenever we order lids from Kols. They only seem to come in the 58mm size for 8oz jars so the damage is limited.
The lids we have are stamped with MRP below the internal gasket material. In looking on the MRP Plastics website, these are polypropylene lids while the inserts are polyethylene (F217 - https://www.oberk.com/closures/continuous-thread-caps-(ct)/plastic-ct-closure/58400ov--58--400-bla-pp-rib-matte-cap-f217-lnr).
F217 inserts are a type of polyethylene foam liner that can be used with metal, plastic, or glass. They are made of three layers: a thin foam core sandwiched between two layers of LDPE film. F217 liners are odor resistant and pulp dust free, and have good chemical resistance and a low transmission rate. They also have a low moisture transmission rate, meaning they prevent moisture from entering the bottle and affecting products.
I would concur with John and Rob that you should check your light sources for UV emissions while also motivating for lights to be off at all times when the space is unoccupied – motion sensitive lights are a great idea.
Hope that helps
Andy
A : A : A :
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Andy Bentley
Ichthyology Collection Manager
University of Kansas
Biodiversity Institute
Dyche Hall
1345 Jayhawk Boulevard
Lawrence, KS, 66045-7561
USA
Tel: (785) 864-3863<tel:%28785%29%20864-3863>
Fax: (785) 864-5335<tel:%28785%29%20864-5335>
Email: abentley at ku.edu<mailto:abentley at ku.edu>
ORCID: https://orcid.org/0000-0002-3093-1258
http://ichthyology.biodiversity.ku.edu<http://ichthyology.biodiversity.ku.edu/>
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From: Nhcoll-l <nhcoll-l-bounces at mailman.yale.edu<mailto:nhcoll-l-bounces at mailman.yale.edu>> On Behalf Of Lance McBrayer
Sent: Friday, March 8, 2024 9:42 AM
To: NHCOLL-new <nhcoll-l at mailman.yale.edu<mailto:nhcoll-l at mailman.yale.edu>>
Subject: [Nhcoll-l] Failure of plastic lids in ethanol collections
Greetings
I have noticed a systematic failure of plastic lids on the top shelves of our wet collection. The plastic is drying and cracking, or crumbling if the lid is pressed in the middle. Luckily I noticed this and only had 3 specimens dry out. But, I'm learning the problem is widespread, particularly on the top shelf.
These lids were replaced in about 2010, and since 2013 been have been kept in a new storage facility with a consistent temp in the 60-69 degree F range.
The facility has shock-proof LED lighting that was supposed to emit little to no UV radiation.
I suspect the lighting is in fact emitting UV. The problem is much less common on the lower shelving racks where they are 'shaded' by jars above. I have also guessed there may be a known 'lifespan' for plastic lids. I bought the lids from O Berk like many collections do in the USA.
Is anyone aware of this problem? That is:
1 - What have others experienced as the lifespan of plastic lids on specimens in 70% ethanol?
2 - Does anyone have suggestions as to how to remedy a UV light issue? There are no windows in the facility. BUT, the safety officer INSISTED on having 2 lights on in the room at all times in case some was in the room and the lights were turned off. I protested, but lost. I think it is time to revisit...?
Any advice forward is welcomed...
Thanks
lm
--
Lance McBrayer
Professor & Curator of Herpetology
Department of Biology
Georgia Southern University
TEL: 912.478.0545
Webpage<https://sites.google.com/a/georgiasouthern.edu/lance-d-mcbrayer/>
--
Lance McBrayer
Professor & Curator of Herpetology
Department of Biology
Georgia Southern University
TEL: 912.478.0545
Webpage<https://sites.google.com/a/georgiasouthern.edu/lance-d-mcbrayer/>
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Stiftung Leibniz-Institut zur Analyse des Biodiversitätswandels
Postanschrift: Adenauerallee 127, 53113 Bonn, Germany
Stiftung des öffentlichen Rechts;
Generaldirektion: Prof. Dr. Bernhard Misof (Generaldirektor), Adrian Grüter (Kaufm. Geschäftsführer)
Sitz der Stiftung: Adenauerallee 160 in Bonn
Vorsitzender des Stiftungsrates: Dr. Michael Wappelhorst
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