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Comment by mandmandam | Hacker News Reader

> I’m surprised to see them characterize the cellulose from a paper teabag as releasing “microplastics.”

I don't think they called cellulose microplastic anywhere. The issue is that commercial teabags these days often aren't using pure paper teabags:

> The tea bags used for the research were made from the polymers nylon-6, polypropylene and cellulose

I believe the polymers are usually coming from the glue keeping the bag together. This is a known issue going back years [0].

0 - https://www.implasticfree.com/why-you-should-switch-to-plast...

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I'm not a chemist, but skimming the paper it certainly sounds like the cellulose itself is what they are measuring:

> Following, ATR-FTIR analysis was performed in the teabags as well as in the leached mixture of nanoparticles plus fibers (Fig. 3). Both teabags and the leachate suspension matched their polymer composition being two of them petroleum-based polymers like nylon-6 (NY6, sample 1) and polypropylene (PP, sample 2), the third one (from the supermarket) being cellulose (CL, sample 3), a bio-based polymer.

I didn't see any mention of plastic binders or other material in the cellulose sample, just references to cellulose.

On the other hand, it was curious that they purchased the synthetic bags empty, but cellulose bags filled with tea, when it is pretty easy to find empty paper tea bags, so maybe there is something particular about the specific type of cellulose tea bag they chose?

For the bags made of cellulose, yes, for the PP and Nylon-6 bags, no:

> To such end, three teabags of different chemical compositions were used in this study: (1) empty nylon-6 (NY6) teabags (as a model of polyamide), (2) empty polypropylene (PP) teabags, and (3) commercially available teabags containing tea, and cellulose as the polymer composition.

keyword being cellulose polymer *composition*, there are hydrophobic additives infused into the cellulose fibers that are proprietary. For example: https://patents.google.com/patent/EP0632163A1/en

Oh my. I hadn’t thought about the adhesives. And just at a gander at the study’s figures, their various microplastic signals from the cellulose bag are hard to distinguish from the pure nylon and polypropylene ones. That’s a sobering thought…

I’ve never seen glued teabags in Europe it’s usually just a metal staple holding them together.

The United Kingdom has a mixture of both types for sale in supermarkets.

How do these “new” pyramid teabags stay in form? I don’t think they use staples…

I don’t know where you are in Europe, but I’ve been to enough of Europe to say that that pretty much everywhere uses teabags that look like this: https://images.app.goo.gl/ZKonRKNqTvfi1qd38.

Sometimes, the top fold is closed over with a small metal staple, but that’s not the only place the bag is sealed.

"To such end, three teabags of different chemical compositions were used in this study: (1) empty nylon-6 (NY6) teabags (as a model of polyamide), (2) empty polypropylene (PP) teabags, and (3) commercially available teabags containing tea, and cellulose as the polymer composition."

The different teabag composition materials were from separate types of teabags, not composition materials of the same teabag.

So that's what I remember hearing this years ago: those silky looking teabags diffuse microplastics. Easy to avoid those.

Er, no. Those silky ones were likely worse, but a lot of the regular looking paper ones have polymer glues releasing microplastic as well.

Do you have any brands in mind? In the bagged tea with cellulose tea bags that I've bought, they are typically held together by just a staple. I've found this to be the case since I occasionally empty the tea from the teabags into my percolator.

PG Tips is a brand that sells those pyramid-shaped teabags that I believe are held together with the glue.

In 2018, Unilever announced that they would soon stop using plastics in their teabags. https://www.theguardian.com/environment/2018/feb/28/pg-tips-...

They've since reformulated the bags - can't find any statement about the new flat bags.

Pillow style tea bags are fully enclosed paper tea bags with no string or tags, and have a crimp around the rim. I never thought about them using glue, but it makes sense. Some brands I know of that use them are Taylors of Harrogate, Celestial Seasonings, Republic of Tea.

Edit: Also some tea bags for loose leaf tea like t-sac or finum brands have that crimp on the edge. However, t-sac confirms they use glue, but finum specifically claims to not use glues, so maybe it is jumping to conclusions that all bags of these sort do.

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