Does anyone know if card sleeves commonly contain Bisphenol A (BPA)? And if so, which brands do, and which are BPA free? I would prefer to use BPA-free sleeves if possible. I have not had any luck finding an answer to this question.
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To answer the question, there are a lot of plastics that are suitable for use as card sleeves. None of them use Bisphenol-A as a plasticizer or monomer; that particular chemical is used primarily to make polycarbonates, which while optically clear are generally too stiff for use as flexible sheets or films (though they're great for applications requiring high impact resistance, like eye protection). So, you don't have to worry about Bisphenol A in your card protectors.
The two plastics you're most likely to see as clear films in your card protectors are poly-ethyl terephthalate (PET), and poly-vinyl chloride (PVC).
PET in fibrous form is known commercially as polyester, though in the chemical industry there are a lot of "poly-esters". This one is formed by bonding ethylene glycol into chains using a phthalate diester to glue them together. As a plastic, it's commonly used in disposable food storage containers, especially soda bottles. It's also commonly used for blister and clamshell product packaging. PET replaced cellulose acetate as a film stock for photos and movies, and also for transparent overlays, so it's definitely got the optical clarity to be used for card protectors.
The dangers of PET come when it's heated. It's perfectly stable at cold to tepid temperatures, making it just fine for packaging refrigerated foods, but when heated it can release the phthalate compounds into the food. Most of us get plenty of exposure to phthalates, and the vast majority do no real harm, but some combinations of alkyl-phthalates are endocrine disruptors which cause hormonal changes, and can cause birth defects and certain cancers.
Poly-vinyl chloride is one of the "wonder-plastics" that was used to do everything, until it fell off its pedestal. It still does a lot; it's seen in drainage and irrigation piping, upholstery, clothing, suction cups, self-adhesive window clings, clear flex tubing, clamshell and bubble packaging, and a host of other uses. It's generally prized for its toughness, even when it's plasticized beyond all recognition; a lot of other polymers lose too much of their tensile strength when too much plasticizer enters the picture.
Now the bad news. First off, the vinyl chloride monomer (VCM) turns out to be carcinogenic; it's fine as a polymer, but people making the stuff and people who come into prolonged contact with severely degraded PVC products can be at risk. Second, most usages of PVC require it to be more flexible than it is in its raw form, requiring the addition of a plasticizer. This is usually a phthalate, like in PET, but here it's a "mix-in"; the phthalate compound works itself into the polymer structure to "loosen" and "space out" the polymer chains, making them flexible. This means they're more readily released under the right conditions (brand-new vinyl products will even "off-gas" excess plasticizer for a few months after they're made and there's not much you can do about it). Some of the phthalates used in PVC cause even more problems than Bisphenol-A; there is evidence to show that a common plasticizer used in PVC piping, di-ethylhexyl phthalate (DEHP), causes feminizing characteristics in males, male obesity, and cardiac problems.
So I guess the moral of the story is, don't put your card protectors in the microwave along with your lunch.
There are a few safe alternatives if you can find them:
BPA is a chemical that has been around for years, and it would be quite difficult to avoid any contact with it anyway.
The studies that claim BPA might pose a danger have methodological issues