We've recently had our own completely 100 % PVC free coin album pages designed and manufactured, you can read about these over at the Purple Penny Coin Accessories website. Our pages are 100% polypropylene, which is a naturally pliable plastic that is very stable and contains no softeners that can leach out onto your coins. They are not the only polypropylene coin holders available on the market, nor are polypropylene and PVC the only materials that are currently used to make coin album pages.
Because of the current interest in the market in storing your coin collection safely (perhaps in no small part to this blog) some album pages are currently being sold as "archival safe" that clearly are not. We know of one page type being sold as archival safe and acid free that is nothing more than a common PVC album page. In the interests of working out what your coin album pages are made from I thought it might be worth discussing the main types of album pages you can find.
Polypropylene Album Pages
Currently the three main types of polypropylene album pages you can find on the market are the Purple Penny album pages mentioned above, Ultra Pro album pages, and BCW album pages. The BCW and Ultra Pro album pages are made from quite thin material and are not very rigid. The Purple Penny pages are made from thicker material and are of comparable rigidity to PVC album pages. Lets look at some of the physical characteristics of polypropylene.
Colour: Colourless
Odour: None
Elasticity: Moderate
Friction: Low
Essentially polypropylene album pages are crystal clear, the plastic is quite 'slippery' to touch, and the material shows good 'stretching' before it will tear. A key thing to note is that polypropylene pages are odourless.
PVC Album Pages
By far the most common album pages on the market, these pages are what you most likely have in your coin albums (shame on you!). They are typically made from thick material (up to 0.2mm thick), are quite stiff, and hold even heavy coins very well. A key thing about PVC to realise is that in it's native state it is not 'soft' or 'flexible', it is in fact a very stiff material with a high modulus of elasticity. Did you know that almost all water pipes and drain pipes in the modern home are made from PVC? Yes the hard brittle white plastic pipes you see on building sites are PVC. So how can soft, flexible coin pages be made from PVC? By the addition of softeners, most typically pthalates. Lets look at some properties of PVC.
Colour: Colourless
Odour: Strong
Elasticity: Limited without softeners, good with softeners
Friction: moderate, can be 'tacky'
PVC album pages are colourless, and quite 'stretchy' and soft. They are not difficult to tear especially when trying to get a 2x2 into an undersized pocket. A key indicator of PVC album pages is the odour. If you've ever opened a new inflatable pool toy you know what this smell is, it is very distinctive and is a combination of the PVC itself and the added softeners. Another indication of a PVC page is in the marketing of the page itself, if it is described as 'soft' then it's almost certainly a PVC page.
Mylar Album Pages
There is one type of album page available that comprises of an outer PVC sleeve into which Mylar (trade name for PET plastic) inserts are placed which hold the coins. Coin holders made form Mylar are distinctive, mylar is quite hard and brittle. It is however odourless and completely inert, and makes an excellent coin holder. SafeT Flips are made from mylar and are an excellent coin holder that is very popular on the US market. One can only wonder why a manufacturer chose to put perfectly good mylar coin holders into a PVC sleeve.
HDPE Album Pages
One last type of album pages you may find on the market are blow moulded type album pages that snap together to hold various types of coin holders. This is the sort of colourless plastic you'll find in toy packaging that protects the toy while allowing the greedy child to see exactly what they want. HDPE coin album pages available in Australian include pages to holder coin slabs and Eagle 2x2 coin holders. HDPE can be a colourless mechanically strong material, but when used to make album pages it is hard with limited flexibility. This is why it is generally used on pages that hold heavier rigid coin holders.
Conclusions
Firstly, don't believe the hype. Either from us or from others. Read, educate yourself, and draw your own conclusions. If a seller says a page is PVC free or 'archival safe' don't take their word for it, look out for that distinctive odour, that 'tackiness' that PVC coin pages show. If you want to know what a page is made from ask the supplier of the page, if they've got nothing to hide they'll tell you. Don't be fooled by buzzwords like 'acid free'. Use your eyes, your nose, and your hands to make your own judgements, and make sure you get the truth about the page. It is, after all your coin collection, and it deserves to be stored in stable, inert coin albums and pages that will not affect the quality of your coins.
Posted by mnemtsas at July 18, 2009 8:53 PM
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