BIO-BASED AND DEGRADABLE PLASTICS

by Ket Bradshaw

Plastics New Zealand

Background

Degradable and bio-based plastics are increasingly entering the market. Bio-based plastics are projected to increase to 10% of the world supply of plastic by 2020.  There are constraints over the supply at this stage.

The main driver for brand owners and retailers choosing degradable and bioplastics relates to concerns about diminishing global oil reserves and an increased demand for products made from renewable resources.  Degradability and bio-based characteristics are seen as attractive attributes.

While degradable plastics have the potential to ‘break down’ in the environment, bio-based plastics come from renewable resources (and also tend to be biodegradable which means they decompose). The five main types of degradable plastics and the range of bio-based polymers are set out in Appendix 1.

Opportunities and Challenges

Bio-based plastics have significant potential in the area where recycling or composting is not currently taking place, for example packaging fruit and vegetables, bakery and deli bags, agricultural twine and silage wrap.  The advantages of these materials are that they are renewable and compostable.

However, there are a number of challenges around these polymers that need to be addressed. These challenges relate primarily to degradable characteristics (including the degradable characteristics of bio-based plastics), and include impacts on recycling streams, misleading claims, and uncertainty of performance.

1. Impacts on Recycling Streams:

In situations where the product is used in similar uses to non degradable plastics, there is a risk that it might contaminate recycling schemes, for example, introducing degradable polylactic acid (PLA) bottles to replace traditional PET.  And while information is unclear, it appears that even at low levels contamination levels of 0.1% (such as 1 bottle in 1000) a small quantity has the potential to disrupt material recycling (through affecting the mechanical properties of the product) and yet be insufficient in quantity to set up a viable alternative recovery infrastructure, for example composting.

Unlike other countries, NZ doesn’t have infrared sorting technology available, making our recyclers particularly vulnerable.  This could have flow on effects to the NZ Packaging Accord in the waste minimisation and recycling area, as it could impact on the 8,000 tonne recycling market for PET.  In 2004 28,000 tonnes of plastic packaging was recycled (20% of the plastic packaging consumed in New Zealand), making PET recycling approximately 30% of the total recycled material.

PLA and PET is the most serious example we are presently aware of. However, in the absence of further information, it is possible that degradable plastics could also have an impact on other existing recycling streams such as bags and film.

2. Misleading claims and uncertainty of performance:

Because of the different types of degradables (see Appendix 1), it’s difficult to know exactly what ‘degradable’ means. It’s also difficult to know just how ‘degradable’ a product really is. So, for example, plastic packaging may claim to be ‘100% biodegradable’, when in fact it will not break down in a home composting environment. 

As a result, some companies are making deliberately or unintentionally misleading claims about performance. The Australian competition watchdog, Australian Australian Competition and Consumer Commission, has already prosecuted successfully in this regard.  Misleading claims also increase the risk of negative consumer experiences by inviting claims of ‘greenwash’.

There are mixed perceptions (in both public and industry) as to what degradable plastics are, how they perform, what the difference is between the different types and how to dispose of them.

A common claim is that these materials disposed into landfill will biodegrade.  This is not desirable as landfills are designed to prevent decomposition. 

What is being done about this?

Plastics NZ (together with the Packaging Council, Ministry for the Environment and local government and Recycling Operators of NZ input), has held two workshops to discuss the issues and solutions. These workshops were a good example of the NZ Packaging Accord in practice, and endorsed an approach be taken similar to Australia. This would see the development of an industry-led Code of Practice (or similar) to oversee labelling, claims, and appropriate applications. This would also be supported by a parallel process to draft the necessary standards for degradable polymers

Plastics NZ has resolved to investigate the development of a NZ Standard, a labelling system and Code of Practice for degradable plastics, by working in conjunction with the Packaging Accord, the Australian Plastics and Chemicals Industries Association (PACIA), RONZ, composters and the Ministry for the Environment.   The overall aim will be to develop a framework for the responsible use of degradable and bio based plastics.

Possible Solutions

We need to manage the impacts of introducing degradable and bio-based plastics into New Zealand.  While the work on industry-led frameworks and standards will help, short term options being considered are:

Appendix 1

Degradable plastics are those that break down by natural processes into the constituent polymer chains. Bio-based plastics are made from renewable resources and are biodegradable which means they breakdown into carbon dioxide, water and organic matter. 

The five main types of degradable plastics and the range of bio-based polymers are:

Sustainable End of Life Options for Plastics in New Zealand, 2005 Plastics New Zealand

NatureWorks LLC PLA RecyclingStream APacific.pdf 2005

Plastics New Zealand is forming a working group to agree on standards, labeling, and an industry code of practice.  Those interested in should please contact:

Jaquetta (Ket) Bradshaw

Environmental Manager

Plastics New Zealand

Mobile: 021 369 495

ket@plastics.org.nz

PACKAGING COUNCIL OF NEW ZEALAND
ACTING AS THE NZ PACKAGING ACCORD SECRETARIAT
77 Greenmount Drive, East Tamaki, Manukau
PO Box 58899, Greenmount, Auckland
PHONE: 09 271 4044, FAX: 09 271 4041