With election season comes the traditional hanging of posters, as candidates of all stripes advertise themselves and their parties. A great many of these posters are made from corflute: a light, cheap, durable sort of plastic, which makes it ideal for outdoor signs. (The specific material branded Corflute is sold by plastic manufacturer Corex.)
But how recyclable is corflute?
Corflute plastic is made from two thin walls of polypropylene, connected by small polypropylene struts – the air sandwich created by this structure keeps the sheet strong and light.
Like all plastics, polypropylene is a polymer made mostly (or in polypropylene’s case, entirely) from carbon and hydrogen. Outside of signage, it’s used in some food containers, straws, and fabrics.
Rigid plastic polypropylene things can be dropped in kerbside bins in most Australian councils. But corflute, and its imitators, typically can’t be recycled like this – it’s too soft, making it likely to tangle in municipal recycling machinery.
Corex runs a recycling program for its material – which is helpful because there are few other places for it to go. Corflute’s polypropylene content makes it a tricky plastic to recycle industrially.
“The thing that’s been holding us back from working with that material is the additional safety precautions that we would need to implement,” says Kayla Mossuto, co-founder of recycling business Precious Plastic Melbourne.
Polypropylene can release fumes when heated – a key part of the thermal recycling process.
“We’d be needing to do more monitoring and managing the fumes, and implementing more PPE such as face masks, along with exhaust systems,” says Mossuto. Precious Plastic focusses on the friendlier polyethylene (HDPE and LDPE) because of this, although they’re looking to expand to other plastics.
But the main trick with these signs isn’t the polypropylene: it’s the stuff around it. Mossuto points out that these posters often come with metal eyelets, stakes, and stickers attached.
“If you have a single material, it’s a lot simpler to work with because it’s just that regular process, but once you bind it with something else, you begin to have issues and it can become essentially unrecyclable,” she says.
While you can print directly on to corflute signs, avoiding the sticker problem, this makes them single-use only.
So, what other options are there? Paper and other more recyclable materials are either too weak to last for a month of campaigning, or much more expensive than corflute, meaning most candidates rule them out.
“A sleeve or a case – even if it’s plastic, a paper poster can be put inside that and then that sleeve or frame or can be reused again and again,” suggests Mossuto.
Cosmos asked the Liberal, National, Labor and Greens parties if they had processes in place for dealing with signs, and all either didn’t respond or said that corflute management was the responsibility of state branches or individual candidates.
This makes sense, since each state and territory has its own rules about when and where you’re allowed to put up campaign posters, leading to a big variation in corflute use. (And in some regions, parties and candidates are pushing to ban plastic signage completely.)
Andrew Wilkie, the sitting independent member for the Tasmanian seat of Clark, tells Cosmos that his office re-uses their corflutes from previous campaigns.
“Ones that are deemed not reusable we try to find a use for. For example, at the last election I gave numerous damaged corflutes to a family who use them under the floorboards as insulation,” says Wilkie.
Meanwhile, campaign volunteers for Helen Haines, the sitting independent member for Indi, Victoria, repaint old corflutes to make into new signs.
Haines’ office also tells us that they’re planning to send their corflutes back to their supplier at the end of the campaign for commercial recycling.
Other candidates have gone looking for interesting applications, too. After the Northern Territory’s 2016 election, ABC radio hosts built a corflute boat called the SS Opposition, made mostly from posters donated by the outgoing Country Liberal Party.
So, even if they’re too hard to recycle, candidates are keen to find other homes for these posters. Understandably, it seems no-one wants their face ending up prominently in landfill.
Nevertheless, there’s probably a greener way to run for government.
Ellen Phiddian is a science journalist at Cosmos. She has a BSc (Honours) in chemistry and science communication, and an MSc in science communication, both from the Australian National University.
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