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 were shipped overseas where they were washed and shredded for reuse as new products. However, one of the key import markets has reduced their demand for plastic waste and in some cases stopped accepting certain types. This means New Zealand is stockpiling plastic waste and sending higher volumes to local landfills.
Some of the plastic types (3, 5, 6 and 7) are more difficult or unprofitable to recycle. In New Zealand, we have relatively small volumes of PVC (3) and polystyrene (6), estimated at 0.19% and 2.47% respectively. However, they have a disproportionately large impact on our recycling system and environment.
Both material types have limited markets in New Zealand and internationally. Reliable access to offshore recycling markets for low-value plastic and less demand is making it more difficult to recycle these plastic types. This has encouraged waste operators to rethink the collection of plastics that are hard to recycle in kerbside recycling.
Oxo-degradable plastics are a type of bioplastic (one of the plastic types making up type 7). Oxo-degradable plastics are made from bio-based materials such as starch or sugarcane or from traditional fossil fuel and include additives to encourage degradation. They only make up a small percentage of plastics in New Zealand but are problematic because they:
- degrade into smaller plastic pieces (such as microplastics) that do not completely go away
- create confusion for the public and businesses who believe it causes less environmental harm than traditional plastic packaging
- contaminate waste streams such as organics and recycling collections
- may have toxic effects on the environment because they haves additives that encourage them to degrade.
Phasing out plastics that are hard to recycle
In June 2021, the government announced a three-stage plan to phase out plastics that are hard to recycle in New Zealand. As part of this plan, a new Plastics Innovation Fund was launched to help support projects that reimagine how we make, use and dispose of plastics.
The plan will roll out across 4 years with the following hard to recycle plastics being outlawed:
- Late 2022: PVC meat trays, polystyrene takeaway packaging, expanded polystyrene (EPS) grocery packaging, degradable plastic products (such as oxo-degradable products), plastic drink stirrers, plastic stemmed cotton-buds.
- Mid-2023: Single-use plastic produce bags, plastic tableware (plates/bowls/cutlery), plastic straws, non-compostable produce labels.
- Mid-2025: All other PVC and polystyrene food and beverage packaging
- The government estimates that this planned phase-out of some forms of problematic plastics will remove more than 2 billion single-use plastic items from our landfills or environment each year.
The government is presently working with stakeholders and business groups to formulate a plan for the phase-out of types of expanded polystyrene, single-use cups and wet wipes.
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.
In the Rethinking Plastics in Aotearoa New Zealand report, Flight Plastics was presented as a positive case study for developing local New Zealand-based closed-loop recycling solutions. Closed-loop recycling is a process by which a product is used, recycled and then made into a new product without ever becoming ‘waste’. Closed-loop recycling systems are important for transitioning from a linear economy where resources are used and then disposed of to a circular economy where plastics are reused and recycled to minimise waste and pollution.
Even with Flight Plastics PET recycling plant, we dispose of more than can be processed. Being forced to find solutions to plastic waste here in New Zealand will hopefully result in more innovation and technological developments in this space.
Plastic is a wicked problem. It’s incredibly useful, but it’s also a huge environmental issue. A helpful resource is Thinking about plastic – planning pathways which includes our interactive planning pathway – use this to begin a cross-curricular look at plastics.
New Zealand science organisations Royal Society Te Apārangi and the Office of the Prime Minister’s Chief Science Advisor have created reports and resources to help us rethink plastic.
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.
Determining the properties of plastic and glass explores similarities and differences in properties of recycling materials with your younger students.
We have curated information from the Building Science Concepts Book 60 Rubbish: How Do We Deal with It? for use in the early to middle primary years.
Learn about plastic products that are to be banned in New Zealand by 2025 and the timeline for the ban in the press release Government takes action on plastics problem.
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.
The Building Science Concepts Book 61 Recycling: New Uses for Rubbish supports the understanding that materials can be classified by their properties.
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.