Recycling Old Plastic Bottles into New

You probably recycle the plastic from your water bottles and other common products packaged in plastic, however, you probably don't know where that plastic goes after it leaves your home. Recycled plastic can make a re-appearance in many products common to daily household use, and can even be turned into industrial or building products, but quite often your old plastic bottle will reappear on a supermarket shelf as a new plastic bottle – here’s how ...

Once the plastic has arrived at a recycling plant, it is either hand or mechanically sorted according to its recycling code. Each plastic type is processed separately. The correct separation of plastics is extremely important - just one PVC bottle in a batch of 10,000 PET bottles can ruin the entire melt!

PET, or polyethylene tephthalate, is semi-rigid to rigid, depending on thickness. It makes a good barrier method, especially for use in soft drink bottles. PET can be produced in a thin film and is also used for flexible food packaging. When recycled, it is made into fibrefill, carpeting, or non-food containers and bottles.

The recycling process begins with the plastic being sliced into flakes which then go through a washing process. After this, the clean plastic flakes are melted together, using specialist heaters, extruded through small holes, and chopped into pellets. These bags of recycled plastic pellets are next taken to factories where they are melted, using mica or ceramic band heaters and cartridge heaters, and made into new products.

When producing plastic bottles, the recycled pellets are fed into a ‘hopper’ and pushed by a screw, turned by a motor, through a heated section set at a temperature high enough to melt the plastic pellets into liquid form. The liquid is then fed into a mould and moulded into preforms.

These preforms are then blown into another mould to form the full size bottle, cooled and removed (this is often done at the bottling plant where they are filled and sealed). This process is called ‘blow moulding’ and is a common industrial process similar to injection moulding and extrusion, that is reliant on specialist heaters.