5 ms·

Can you elaborate ? What's wrong with cans ? If they're aren't just aliminum what are they coated with on the inside ? How would tetrapak fare better ?

deleted 4y ago
[deleted]
exhilaration 4y ago
It has changed now but, "For decades, most canned food manufacturers used can linings made of epoxy resin based on bisphenol A, or BPA, making food the primary route of our exposure to this toxic chemical." From here: https://www.ewg.org/news-insights/news/bpa-update-tracking-canned-food-phaseout https://www.ewg.org/news-insights/news/bpa-update-tracking-c...
- elil17 4y ago
  BPA is still used widely. BPB is sometimes used as a substitute but it’s probably just as bad.
  - MengerSponge 4y ago
    For people who care: thermopaper receipts are absolutely loaded with BPA. Cashiers have measurably higher serum BPA levels, because they touch them all day long. I generally don't take or touch receipts if I can avoid it, but I don't treat them like they're radioactive. The dose makes the poison, and I haven't figured out how to completely eliminate them and still function in society.
    - trafficante 4y ago
      With the initial Covid protocols training everybody into becoming constant receptacles for hand sanitizer, thermal receipt paper is probably worth being concerned about at this point. Using hand sanitizer increases the absorption rate of BPA and other chemicals by a factor of 100 or more - https://www.newsweek.com/hand-sanitizer-speed-absorption-bpa-receipts-279232 https://www.newsweek.com/hand-sanitizer-speed-absorption-bpa...
      - 6510 4y ago
        printing with ink is not madly expensive. Thermal paper should just be banned. Its a ridiculous product anyway the way it just goes blank long before the warranty expires. https://www.digitalcheck.com/receipts-thermal-ink-costs/ https://www.digitalcheck.com/receipts-thermal-ink-costs/ > There’s one other small difference that’s become important in the battle between thermal and ink: the use of company logos on receipts. As it turns out, this is a key factor in the cost of paper, and tips the break-even point in favor of thermal if you want your receipts to have a distinctive look. Ordinarily, plain receipt paper can be had for as little as 40 cents per 150-foot roll, while thermal paper comes in longer rolls (220 or 230 feet) that cost around 80 cents – so you get 25-30% more paper for your dollar with the standard variety.
        bornfreddy 4y ago
        > Its a ridiculous product anyway the way it just goes blank long before the warranty expires. This might be another reason why companies use it. No receipt, no warranty associated costs. We usually photograph such receipts so that we can print them if needed. But it's annoying.
        6510 4y ago
        Besides killing the customer, how is using magic ink even legal?
      - rootw0rm 4y ago
        as a random aside...sanitizer reacts instantly with thermal paper, darkening the paper
    - bb88 4y ago
      link?
      - MengerSponge 4y ago
        Search: cashier serum bpa Example study: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4927604/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4927604/
        bb88 4y ago
        Amazing. Thanks.
    - exhilaration 4y ago
      BPA-free thermal paper is available and some chains have switched. For example: Costco warehouses in the U.S. and Canada have changed their receipt paper so that it is phenol-free. This means it does not contain Bisphenol A (BPA) and Bisphenol S (BPS), which have been linked to human health concerns. - https://www.costco.com/sustainability-chemical-management.html https://www.costco.com/sustainability-chemical-management.ht...
      - MengerSponge 4y ago
        Cool! I just learned about this: https://www.pca.state.mn.us/green-chemistry/bpa-thermal-paper https://www.pca.state.mn.us/green-chemistry/bpa-thermal-pape... Because my consumer-grade fingertips don't run mass spec, I'm going to continue not touching receipts as much as possible. Hopefully some people who read this have a connection to a company that issues printed receipts.
deleted 4y ago
[deleted]
elil17 4y ago
They have an epoxy coating with on the inside which contains BPA or BPA substitutes like BPB. Tetrapaks have a polyethylene liner and polyethylene and typically doesn’t have plasticizers added.
- robryk 4y ago
  Do you know why the two plastics are different? I would naively expect that everything that would work as the inner layer in tetrapak would also work in cans (cans deform less). Is it that making the layer stick to tetrapak is simpler/different than making it stick to metal?
  - jfim 4y ago
    I'm not a material scientist, but the two are constructed very differently. Tetrapaks are laminated, meaning that various layers of solid materials are glued together. Think of it as a sticker on something. For cans, the epoxy is a liquid coating that's applied by spraying or roller coating, more like paint.
    - coryrc 4y ago
      And, for the cans, it then cures in place. The BPA is like a catalyst and doesn't bind with the material, which is what allows it to leach out so well. Polyethylene, in addition to being a safer molecule, uses catalysts which don't end up in the final product, which means you can't be exposed to them.
      - smohare 4y ago
        “Leach out so well”. Sounds like you never read the studies around how it leaches, lol.
TheSpiceIsLife 4y ago
Food cans are made of steel, only drink cans are made of aluminium.
discordance 4y ago
Aluminum cans are lined with plastic - https://youtu.be/xBQEnVR7y9k https://youtu.be/xBQEnVR7y9k
- smohare 4y ago
  For good reason. Fucking troll.
  - dang 4y ago
    We've banned this account for repeatedly breaking the site guidelines. If you don't want to be banned, you're welcome to email hn@ycombinator.com and give us reason to believe that you'll follow the rules in the future. They're here: https://news.ycombinator.com/newsguidelines.html https://news.ycombinator.com/newsguidelines.html.

deleted 4y ago

[deleted]

exhilaration 4y ago

It has changed now but, "For decades, most canned food manufacturers used can linings made of epoxy resin based on bisphenol A, or BPA, making food the primary route of our exposure to this toxic chemical." From here: https://www.ewg.org/news-insights/news/bpa-update-tracking-canned-food-phaseout https://www.ewg.org/news-insights/news/bpa-update-tracking-c...

elil17 4y ago
BPA is still used widely. BPB is sometimes used as a substitute but it’s probably just as bad.
- MengerSponge 4y ago
  For people who care: thermopaper receipts are absolutely loaded with BPA. Cashiers have measurably higher serum BPA levels, because they touch them all day long. I generally don't take or touch receipts if I can avoid it, but I don't treat them like they're radioactive. The dose makes the poison, and I haven't figured out how to completely eliminate them and still function in society.
  - trafficante 4y ago
    With the initial Covid protocols training everybody into becoming constant receptacles for hand sanitizer, thermal receipt paper is probably worth being concerned about at this point. Using hand sanitizer increases the absorption rate of BPA and other chemicals by a factor of 100 or more - https://www.newsweek.com/hand-sanitizer-speed-absorption-bpa-receipts-279232 https://www.newsweek.com/hand-sanitizer-speed-absorption-bpa...
    - 6510 4y ago
      printing with ink is not madly expensive. Thermal paper should just be banned. Its a ridiculous product anyway the way it just goes blank long before the warranty expires. https://www.digitalcheck.com/receipts-thermal-ink-costs/ https://www.digitalcheck.com/receipts-thermal-ink-costs/ > There’s one other small difference that’s become important in the battle between thermal and ink: the use of company logos on receipts. As it turns out, this is a key factor in the cost of paper, and tips the break-even point in favor of thermal if you want your receipts to have a distinctive look. Ordinarily, plain receipt paper can be had for as little as 40 cents per 150-foot roll, while thermal paper comes in longer rolls (220 or 230 feet) that cost around 80 cents – so you get 25-30% more paper for your dollar with the standard variety.
      - bornfreddy 4y ago
        > Its a ridiculous product anyway the way it just goes blank long before the warranty expires. This might be another reason why companies use it. No receipt, no warranty associated costs. We usually photograph such receipts so that we can print them if needed. But it's annoying.
        6510 4y ago
        Besides killing the customer, how is using magic ink even legal?
    - rootw0rm 4y ago
      as a random aside...sanitizer reacts instantly with thermal paper, darkening the paper
  - bb88 4y ago
    link?
    - MengerSponge 4y ago
      Search: cashier serum bpa Example study: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4927604/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4927604/
      - bb88 4y ago
        Amazing. Thanks.
  - exhilaration 4y ago
    BPA-free thermal paper is available and some chains have switched. For example: Costco warehouses in the U.S. and Canada have changed their receipt paper so that it is phenol-free. This means it does not contain Bisphenol A (BPA) and Bisphenol S (BPS), which have been linked to human health concerns. - https://www.costco.com/sustainability-chemical-management.html https://www.costco.com/sustainability-chemical-management.ht...
    - MengerSponge 4y ago
      Cool! I just learned about this: https://www.pca.state.mn.us/green-chemistry/bpa-thermal-paper https://www.pca.state.mn.us/green-chemistry/bpa-thermal-pape... Because my consumer-grade fingertips don't run mass spec, I'm going to continue not touching receipts as much as possible. Hopefully some people who read this have a connection to a company that issues printed receipts.

deleted 4y ago

[deleted]

elil17 4y ago

They have an epoxy coating with on the inside which contains BPA or BPA substitutes like BPB. Tetrapaks have a polyethylene liner and polyethylene and typically doesn’t have plasticizers added.

robryk 4y ago
Do you know why the two plastics are different? I would naively expect that everything that would work as the inner layer in tetrapak would also work in cans (cans deform less). Is it that making the layer stick to tetrapak is simpler/different than making it stick to metal?
- jfim 4y ago
  I'm not a material scientist, but the two are constructed very differently. Tetrapaks are laminated, meaning that various layers of solid materials are glued together. Think of it as a sticker on something. For cans, the epoxy is a liquid coating that's applied by spraying or roller coating, more like paint.
  - coryrc 4y ago
    And, for the cans, it then cures in place. The BPA is like a catalyst and doesn't bind with the material, which is what allows it to leach out so well. Polyethylene, in addition to being a safer molecule, uses catalysts which don't end up in the final product, which means you can't be exposed to them.
    - smohare 4y ago
      “Leach out so well”. Sounds like you never read the studies around how it leaches, lol.

TheSpiceIsLife 4y ago

Food cans are made of steel, only drink cans are made of aluminium.

discordance 4y ago

Aluminum cans are lined with plastic - https://youtu.be/xBQEnVR7y9k https://youtu.be/xBQEnVR7y9k

smohare 4y ago
For good reason. Fucking troll.
- dang 4y ago
  We've banned this account for repeatedly breaking the site guidelines. If you don't want to be banned, you're welcome to email hn@ycombinator.com and give us reason to believe that you'll follow the rules in the future. They're here: https://news.ycombinator.com/newsguidelines.html https://news.ycombinator.com/newsguidelines.html.