As long as the paper isn't in direct contact with the coins, which it shouldn't be in a
flip pocket, there's not much to worry about. I used to
work in a paper mill years ago, and learned quite a
bit about production techniques. Most of the paper produced these days is acid-free, because paper companies use chalk as the main filler material in the paper pulp since chalk is cheaper than
china clay that was used as pulp filler in the past. Chalk will react with acids in the pulp, and therefore requires paper companies to make the pulp chemically neutral or alkaline.
As for paper bleached with chlorine, virtually all
North American
mills converted to "elemental chlorine free" processing to whiten the pulp in 1990. As a matter of fact, the
Alliance for Environmental Technology posts an annual report on ECF paper stating that 89% of the world's paper production is now "elemental chlorine free."
There are actually three
types of chlorine free paper processes:
1. ECF can sometimes
still use a chlorine derivative, primarily chlorine dioxide, which is much less reactive. Elemental Chlorine-Free indicates virgin or recycled fiber that is bleached with chlorine dioxide or other chlorine compounds. This process significantly reduces hazardous dioxins, but does not completely eliminate them.
2. PCF Processed Chlorine-Free a paper with some or 100 percent recycled fiber content. The recycled fiber in the sheet is unbleached or bleached with non-chlorine compounds, but as we don't know how the original paper was treated, we cannot consider it totally chlorine-free.
3. Totally Chlorine-Free means that 100 percent virgin fiber (including virgin tree-free fiber) is unbleached or bleached with non-chlorine compounds. It may also include
wood or alternative fibers, such as kenaf. The term TCF cannot be used on recycled paper because the treatment of the original paper is unknown.
Look for the ECF, PCF, or TCF label on the next ream of paper you purchase. If you are in
North America, you shouldn't have to worry at all about chlorine leaching from the paper, as the 11% of paper
still produced by chlorine gas beaching processes are made in mostly small, semi-industrialized nations. If you are
still worried about the small amount of chlorine derivatives remaining in regular paper, you can always switch to cotton rag fiber paper, which is archival, acid free, and totally chlorine free... and is made to last for up to 1000 years. As for me, I'd stick with the cheaper, regular paper and let my great great grandchildren change out the
flip inserts if they start to tone the coins a few generations from now.
