Over the last 50 years, plastics have become an integral part of our world. Plastic products are found everywhere – in our houses, cars, bikes, toothbrushes and even our clothes. Plastics were first formed using natural materials containing long polymer chains that could be stretched and moulded into different shapes. The term ‘plastic’ is from the Greek word ‘plastikos’ meaning it can be moulded or shaped.
What is plastic?
Plastics are formed from materials that have similar molecules linked together to form long chains. They are primarily made of carbon and hydrogen molecules and sometimes are formed with other atoms such as nitrogen, oxygen, chlorine, sulphur, silicon, fluorine or phosphorus.
Plastics are mostly comprised of materials found in nature, such as plants, trees, oil, coal and natural gas. One of the first synthetic plastics formed used cellulose from plants that was heated with chemicals, resulting in a new material that was extremely durable.
PET plastic is very common. It is the clear plastic that is used for bottled drinks, like water and soft drinks. It also is used for packaging for food, like fruit and biscuits. PET or PETE stands for polyethylene terephthalate and is a safe, non-toxic, strong, lightweight material that is 100% recyclable. It can be identified by looking at the recycling stamp – PET or PETE is stamped with a 1.
Why has using plastic become an issue?
Food safety regulations have improved consumer confidence when purchasing food items in PET plastic. However, this also means large amounts of single-use plastic containers and packaging are created. The single-use waste stream creates one of the largest amounts of plastic waste in the world.
PET recycling process
Local recyclers pick up PET and other plastics and sort them by their resin identification code (RIC) numbers – numbers 1–7. Each plastic has a unique ‘fingerprint’ or chemical make-up. Keeping the plastics separated preserves the material’s value and means it can be recycled for reuse. The different plastics are crushed, baled and sent away for processing. Up until recently, most of the plastics recycled here in New Zealand have been shipped overseas for processing and reuse, or they are dumped. Overseas companies process PET into small flakes called RPET (recycled PET).
Flight Plastic packaging – a New Zealand first
Flight Plastics, a company based in Lower Hutt, has a 40-year history in producing plastic packaging. In 2013, Flight began importing RPET to make new PET packaging. In 2017, it closed the recycling loop by opening New Zealand’s first PET wash and recycling plant.
New Zealanders use over 20,000 tonnes of PET plastic resin each year, and most of it enters the New Zealand waste stream after use. Flight uses state-of-the-art technology to turn this waste into new food-grade packaging. Cleaning and sorting are two key steps to creating RPET flakes.
Nature of science
New technology is often produced in response to an issue – in this case, tonnes of plastic waste going to landfill. In order for the technology to be useful in a business, it is required to be fast and cost-effective. The technical design details of specific technology is often kept confidential when produced commercially. Scientists, developers and engineers will be employed by companies to develop and fine-tune technologies.
The wash plant is key to recycling PET plastics locally. The bottles and containers go through numerous wash cycles. The glues holding the labels are not all the same, so it may take multiple washes to remove them.
Flight is serious about sustainability – it filters and reuses the wash water. Waste water is held on site for 24 hours, where it is monitored for pH and other indicators before release to the local wastewater treatment plant.
Detection and sorting technology
Sorting technology is also key to making RPET. Magnets separate metal from the plastic. Some items have multiple materials within them. For example, foam-handwash bottles have small springs in the plastic tops. The springs are removed once the plastic is crushed off them.
Flight uses advanced technology to sort non-PET flakes from the mix. To the naked eye, small plastic flakes often appear the same. Flight’s sorting technology detects the different types of plastic using a combination of optical sorting – near infrared and visual wavelengths. Sensors detect the non-PET flake, and a jet of air removes it from the conveyor. The material is screened multiple times as it is granulated and washed.
The final product is small, clean pieces of pure RPET plastic. It takes just 30 minutes for a discarded PET bottle to be turned into clean flakes suitable for new food-grade packaging.
What impact does this have?
Making a choice to buy products that have a Flight packaging stamp on them means you are reducing the amount of new PET plastic production, diverting PET from landfill and conserving our natural resources. In addition, recyclers no longer have to ship PET plastic overseas, and Flight no longer has to import RPET flakes. Flight Plastic packaging can be recycled over and over again.
Reduce, reuse and recycle – be a conscious consumer.
Flight Plastics has a long history in producing plastic packaging, with over 40 years in the plastics industry. The company is New Zealand owned and is committed to constant investment in new technologies and its highly skilled people.
During the 1970s, Flight Plastics pioneered local production of PET by being the first company in Australasia to produce PET rollstock and thermoformed plastic containers. Now Flight is the first company producing eco-friendly RPET rollstock and finished containers all under one roof.
The Science Learning Hub acknowledges the collaboration with Flight Plastics in the production of this article.