Different types of recycled plastic

Experiment #7 – LDPE and PP

I’ve finally moved from melting milk bottle lids to trying out other types of plastic, specifically LDPE plastic bags and corrugated plastic signs from PP. And it’s definitely harder using my primitive equipment.

Polypropylene or #5 PP

There’s a local election this year, and I know that thousands of corrugated plastic signs will go to landfill unless there’s a recycling solution. So, if I can find a way to do this, I could do a good thing for the environment and really demonstrate the value in this discarded resource.

Election signs
Credit: Canberra Times

For the corrugated plastic signs experiments, I was specifically trying to maintain the original designs of the sign. That’s been tricky because I found it easy to burn the added ink in a convection oven. Furthermore, PP or polypropylene melts at a much higher melting point then the others and I’m finding it harder to get it to melt fully in my moulds.

Below shows my first experiments. The right “coaster” was obviously burned in the process. The one on the left wasn’t as much as I put aluminium foil over the top of it, but there are still solid pieces that weren’t full melted.

Polypropylene
Failed PP experiments

Low-density polyethylene or LDPE #4

For LDPE, I’m trying to solve another problem that was brought up by my mates at Pushy’s Bike Store. Every bike and part that they receive comes in a plastic bag, and they have no way to recycle it.

It’s a good, clean source of mostly LDPE plastic. Furthermore, I reckon that just about every retailer in Canberra has the same issue. For Pushy’s specifically, I also asked them to give me some discarded bike gears and chains too.

My thoughts were that I might be able to embed the parts into the plastic to tell a better story of where the plastic originally came from.

Telling the story of these plastics

One of the major reasons why I have gone the extra lengths to keep the artwork on the plastic (from milk bottle lids to the signs) is to be able to share the story of where these plastics came from.

If everything is a single colour, few people will even know that it’s recycled plastic in an end product. If it comes in the typical multiple-colour tones that are the results of shredding the material without further processing, people may know it’s from recycled plastic, but they have no idea from what.

I want people to see value in this resource, and it’s much each easier to share their origin’s story if I can somehow keep the artwork when I turn it into a final product. Plus, how cool would it be if I can pull it off!

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Tammy Ven Dange

Purpose Driven Entrepreneur Be kind to animals and mother nature!

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