Soft-plastic recycling – research and feasibility
Dear Precious Plastic community,
I am intern in Swiss research institute working on waste management. A waste audit in one of our nepalese case studies highlighted the need for treatment solutions for soft plastics (mainly food wrappers, approximately 10kg/day). For the next two month we will be conducting a research in Nepal on Small scale soft plastic recycling.
Among my tasks, I’ll be working with a local NGO to achieve and document the construction of a compression machine.
I’ll keep you updated on our progress through this post and I’m happy to hear about your suggestion, experience, comments, etcetera.
Suscribe to the post to stay updated!
All the best,
@marcvdv – that’s odd. the link still works for me. It goes to:
@frogfall Apparently this website is blocked from Nepal (For telling the truth?). I could access it through my VPN.
Weekly update # 4 (2/2)
Following @donald ‘s links (thank’s, I should improve my research skills) I found out how difficult it was to recycle PET compared to PP. Moisture makes PET recycling challenging and now it’s monsoon time in Kathmandu. An additional step of drying would therefore be needed to limit PET’s breakability (more info on this nice link). @microtransactions built a vaccum drying system for extruding PET, I don’t know what’s the conclusion of this (see these links: link1 link2
Given the limited time we have, considering drying add a degree of complexity to a process that I have to present as simple and easy to replicate. So I think we won’t focus on recycling these PET wrappers on this project.
Noodle packages in Nepal consist in fact of two layers. An inner transparent PP layer and an outer PET metallized layer. The two layers can relatively easily be separated by hand (it’s like unsticking a sticker from plastic matterial; depending on the wrapper’s condition).
The inner layer melts nicely at 210°C and produces a solid and resistant chip. The outter one can be melted around 270°C but leads to a brittle result (as with the PET biscuits).
I’m now considering to iron these outer layer together (not sure it would hold, though) to product some kind of canvas sheet. Otherwise, if none of you guys have an easy suggestion to cope with PET brittleness, we’ll focus on other wrappers. Future research could also focus on how to separate these two layers on a bigger scale (out of the scope of our project, but if you have suggestions, I’ll document it in my report).
Today, we started melting different wrappers to see how they behave at 210°C. Many of them (metallized or not) melted nicely and allow us to press small chips (see third picture below). We are listing the PP wrappers (melting at 210°C) as well as the other/mixed wrappers to ease future replication.
For the time we have left (approximately 2 weeks) we will focus on gathering enough of these PP wrappers and to mold an usefull object (most probably small sheets to make paper boards), as a proof of concepts for the locals. We hope to end our fieldwork with a workshop/demo/discussion day.
As usual, any question, feedback, comment is welcome!
The PET sounds challenging. I guess it depends on what the overall problem that is trying to be solved. If the issue is to avoid having these pouches littering the countryside, then the brittle chunks are an improvement. Perhaps the brittleness can be used to crush it and use it as an aggregate in bricks, pavers, retaining blocks, etc. made from other plastics. Kind of like the sand is being used in making plastic roof tiles and bricks.
Interesting that you are slowed in your work by insufficient plastic material.
2 weeks is a very short time, so focusing on a working PoC would be key for your research, but I also agree with Stan @s2019 that ‘teasing’ the PET as a potential building material (bricks/tiles, mixed with sand) “if only you had more time…” would also keep the momentum going.
PM me for a more ‘tactical’ approach or if you want me to mail you the @frogfall webpage (I can confirm it works) 😉
@s2019 Maybe a few more words on this “plastic supply” issue could be intersting for you. Don’t take me wrong: these wrappers are laying all over the place. We partnered with a local organization to collect this material for us but it took more time than expected (someone threw away the wrappers that were saved for us).
Indeed, it could be interesting to assess the construction material opportunities. Pilot portions of “plastic roads” have been built recently (600kg waste for a 200m street). But if PET is brittle, could we still make durable construction material, without other plastic/crude oil?
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