Plastic is an amazing material. It has changed the way we store and carry food, drinks and other items. Plastic is lightweight and resists breaking when dropped. Older people may remember when shampoo came in glass bottles – and what happened when the bottle slipped out of soapy fingers while in the bath!
Lightweight, unbreakable plastic packaging also reduces production and transportation costs. Plastics have given us durable, weather-resistant building products. Plastic pipes resist mildew, mould and insects – and a lot of our outdoor clothing, from polar fleece to puffer jackets, is made from plastic!
Plastic packaging – a short history
The first plastic products were made from cellulose – a natural product from plants and trees – in the 1860s. Named ‘Parkesine’ after its inventor, the material was mouldable when heated but kept its shape when it cooled down. The first totally synthetic plastic was called Bakelite. It became known as the material of a thousand uses. Most New Zealanders would have had at least one Bakelite item in their homes – their telephones.
Plastic food wrap – known as Saran – was produced in 1933. Although it was first used to protect military equipment, people saw how well it could cling to items like bowls. A decade later, Tupperware was invented. These airtight food containers changed the way we stored food. Another milestone came in 1978 when Coca-Cola introduced the world to the 2L PET bottle. Much of the world had been buying milk in plastic bottles since the 1970s, but New Zealand held on to reusable glass bottles until they were phased out in 1989.
Nature of science
Plastics are a product that has changed the way we live. Foods stay fresher, babies and toddlers can safely carry their drink bottles and packaging means items remain undamaged. Science has created a product that is integral to our everyday lives but has also created a socio-scientific issue with the enormous amount of waste it creates.
Too much of a good thing
Plastic products and packaging became so popular that the amount buried in landfills was of concern to many New Zealanders. Towns and cities established recycling depots and kerbside collection recycling schemes for some plastics, glass and paper. By 2006, nearly 75% of Kiwis could have their recycling picked up from their homes. Today, most New Zealanders have access to recycling schemes. The Ministry for the Environment reports that, in 2010, 94% of New Zealand households participated in recycling, with three-quarters of people recycling all or most of the items they know can be recycled. However, only an estimated 14–18% of plastic waste is recycled globally.
The science behind plastics and recycling
All plastics are made out of hydrogen and carbon atoms (known as hydrocarbons) that are processed into long chains of molecules called polymers. ‘Poly’ means many, so that is why many plastic names begin with poly. Most hydrocarbons come from oil and natural gas. Other additives are mixed in during the processing to form different plastic materials with special characteristics.
Manufacturers use special names for the different plastics, but most of us recognise them by their resin identification code (RIC) numbers. For example, plastics made out of polyethylene terephthalate (PET) are marked with the number 1. High-density polyethylene (HDPE) products are marked with the number 2.
Plastic products have these numbers to make it easier to sort and separate items for recycling. Keeping the plastics separated preserves the material’s value and means it can be recycled for reuse.
What happens to the recycled materials?
Regional and local councils in New Zealand have a range of approaches to the types of plastics they collect for recycling. Plastics marked 1 and 2 are universally accepted in mainland New Zealand. The various household plastics are collected at the kerbside or at recycling depots. The products are sorted by RIC numbers, squashed and baled, and most are shipped overseas, depending on global demand. There, the plastics are washed and shredded for reuse as new products.
Some of the plastic types (3, 5, 6 and 7) are more difficult or unprofitable to recycle.
The changing industry of recycling
Until 2017, none of the PET collected in New Zealand was processed for reuse locally. It was sorted and then sent overseas to be processed or dumped. In the past, New Zealand has relied heavily on exporting our plastic waste to other countries such as China. Recent restrictions and a tightening of regulations has meant that China and other countries are not importing as much waste plastic, and here in New Zealand, stockpiles of waste plastic for recycling are growing.
Flight Plastics, a company based in Lower Hutt, imported recycled PET (RPET) flakes to make new PET packaging. In 2017, it opened New Zealand’s first PET wash plant, enabling Flight Plastics to close the recycling loop. Now, used PET plastic collected locally is baled and sent to Flight Plastics for processing and recycled into new packaging for many of your favourite foods. If you recycle a Flight Plastics container or package, it can be made into a new product over and over again.
Even with Flight Plastics PET recycling plant, we dispose of more than can be processed. Being forced to find a solution here in New Zealand will hopefully result in more innovation and technological developments in this space.
Find out more about the technology that Flight Plastics uses to sort and recycle PET plastics.
These resources support students in levels 1–4 with learning about waste and recycling.
Read the level 4 Connected article Turning old into new to discover where plastics and other materials come from and how we can minimise our ecological footprint.
When we throw something away, how do we know where ‘away’ is? The Sustainable Seas National Science Challenge is developing online tools to help us find out. Ocean Plastic Simulator is an interactive computer simulation that shows where plastic is likely to end up when it is dropped in the ocean.
The wiseGEEK website has a simple yet detailed explanation of how plastic is made.
Watch this 1989 news story on the transition from milk in glass bottles to plastic packaging.
Watch this Seven Sharp video to view Flight Plastics’ new recycling system.
What is it like to pick up kerbside recycling? Read one perspective in this Stuff article. (Remember to rinse your recycling!)
Plastics in the Environment: Te Ao Hurihuri – The Changing World is an expert advice summary released by the Royal Society Te Apārangi. It is available as a PDF to download and contains some useful infographics.
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.