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The Life Cycle of a Plastic Bottle

How are plastic bottles recycled? How are they made in the first place? When you toss a plastic bottle into the recycling, do you ever wonder where it goes? Recycling is part of our everyday lives, and yet the process after our bins have been emptied seems shrouded in mystery. It’s actually an interesting journey, though, so let’s take a look at the life cycle of a plastic bottle.


How are plastic bottles made?

There are different sorts of plastic bottle, of course! For example, most drink bottles are made of a transparent plastic called polyethylene terephthalate, or PET. If you can see through the bottle to the liquid inside, it’s probably PET. Detergent bottles are usually made of a harder plastic called high-density polyethylene, or HDPE.

Plastic bottles are usually made using a technique called blow-moulding. It works like this:

  1. Lots of small pellets of plastic are melted down. 
  2. The melted plastic is injected into a mould to create a hollow plastic tube, which is open at one end; that’s where the cap will go on later. This tube is called a preform. It sometimes looks a bit like a large test tube.
  3. The preform is put into a bottle-shaped mould. If it isn’t still warm, it’ll need to be warmed up first, to make it softer and easier to shape.
  4. A machine injects air into the preform, and the plastic expands to fit the mould.
  5. The bottle is cooled down so it’ll keep its shape.

The empty bottles are shipped to the bottling plant, where they’re filled with whatever they’re supposed to hold — water or detergent, for example — and the caps are put on. After that, the bottles go off to the shops.

The next part is the part you already know! You buy the bottle from the shop, and you drink or use whatever’s inside.

Next, it’s time to think about how to recycle plastic bottles. If you throw the bottle into the household waste when you’re finished with it, it’ll go to landfill, which means all that useful plastic will be wasted and it’ll take hundreds of years to decompose. It’s much better to put it in the recycling.


What can plastic bottles be recycled into?

At the recycling centre, the bottle will be melted down and used to make something new.

You’ve probably already guessed this one, but it might be recycled to make new bottles, starting the life cycle of a plastic bottle again.

What you might not have realised is that melted PET bottles can also be spun into polyester fibres. This means that plastic bottles can be turned into carpets, clothes or the warm lining for sleeping bags, for example. Some of the polyester in your favourite fleece might come from a bottle you once drank out of!

Detergent bottles, made of HDPE, have even more exciting uses. They can be turned into bins, rulers, or even furniture.

The caps on bottles can be recycled as well, so you can usually leave them on your bottles when you put them in the recycling bin, although you might want to check your local council’s policy about this. They might be turned into plastic bags, or used to make casing for car batteries.


So that’s what happens to plastic bottles, from the factory to a new life as something else! Next time you sit on a plastic bench, remember that you might once have used it to pour detergent into your washing machine.

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