Due to the convenience and cost, plastic bottles are becoming more and more prevalent in use as containers for all kinds of food and household items. The type of plastic used for clear bottle production (while there are many types of plastics and plastic bottles, clear plastics are the most widely used) is called polyethylene terephthalate (PET, or PETE). The journey from PET raw material to becoming a clear plastic container is a long, but sometimes fascinating one. Let’s have a look at that process, and see what we can learn about bottle production.
First, at a manufacturing plant, an automated mixer blends raw PET flakes with 10 percent recycled plastic. Plastic losses some of its properties in the recycling process, so, unfortunately, there is a limit to how much can be used in the new product. The mixture is then heated to a blazing 600 degrees fahrenheit, where the compound is melted and highly malleable. It is then shot at high pressure into a mould, which creates the initial bottle or jar-like shape, called a ‘preform’.
The hot preforms harden instantly, due to the machine’s built-in cooling system. Another machine then takes over. Its job is similar, in that it heats the preforms until they are malleable. Each container is then shaped into the appropriate bottle or jar-like form, helped along by another system of heaters and coolers. During this process yet another machine sneakily melds a piece of plastic to the bottom of the bottle or jar to give the container added strength.
Only once the container has entirely cooled can it be removed from the mould. This newborn bottle or jar will need some trimming before it is ready to be packed up and shipped off to be filled up and debut as a jar of peanut-butter or bottle of cola.
Of course it is all a bit more technical than this, and we may have left out some of the more unfamiliar terms. But this is a good overview to how simple raw PET material gets transformed into usable, convenient plastic containers. Speaking of which, stop by the All In Packaging site to see some of the results of plastic bottle production.