What is the AS4736 standard for biodegradable plastic?
If a plastic material claims to be biodegradable and compostable in Australia, it must comply with Australian standard AS 4736‐
2006. This standard provides assessment criteria for plastic materials that are to be biodegraded in municipal and industrial
aerobic composting facilities. This Australian standard is similar to the widely known European EN 13432 standard, but has an
additional requirement of a worm test. In order to comply with the AS 4736‐2006, plastic materials need to meet the following
minimum of 90% biodegradation of plastic materials within 180 days in compost
minimum of 90% of plastic materials should disintegrate into less than 2mm pieces in compost within 12 weeks
no toxic effect of the resulting compost on plants and earthworms.
hazardous substances such as heavy metals should not be present above the maximum allowed levels
plastic materials should contain more than 50% organic materials.
This standard was prepared by the Standards Australia (ww.standards.org.au) to assist authorities regulate polymeric materials
entering into the Australian market. In turn, the Australian Bioplastics Association (ABA) leverages a third‐party verification system
to assist manufacturers, distributors and retailers to communicate their compliance to this standard hence verify product quality
with respect to biodegradability claims.
What are Bioplastics?
Bioplastics encompasses a whole family of materials which are biobased, biodegradable, or both.
Derived from renewable biomass sources, such as plant based starch, sugarcane or cellulose, Bioplastics are already used in packaging, agriculture, gastronomy, consumer electronics and automotive industries, just to name a few.
Bioplastic materials are used to manufacture products intended for short term use, such as mulch films or catering products, as well as durable applications, such as bottles, mobile phone covers or interior components for cars. Some common applications of bioplastics are packaging materials, dining utensils, food packaging, hygiene products and insulation.
What differentiates bioplastics from conventional plastics?
The term bioplastics encompasses a whole family of materials which are biobased, biodegradable, or both.
What is the Australasian Bioplastics Association (ABA)?
Since 2006, the ABA’s principle aims are to be the voice of the bioplastics industry and to facilitate the market introduction of bioplastics throughout Australasia. The ABA’s program is supported by Compost Australia (the Association of Commercial Composters), DEHWA (Department of Environment and Heritage) and PACIA (Plastic and Chemical Industry Association) as well as a cross section of suppliers, manufacturers and retailers.
How can I claim my product meets AS4736 standard?
The ABA has launched the ‘seedling logo’ certification system throughout Australia and New Zealand. The seedling logo is used to clearly identify certified compostable packaging materials. To be certified compostable and carry the seedling logo, suitable biopolymer materials must undergo a stringent test regime outlined by AS4736 and carried out by recognised independent accredited laboratories1 to the AS4736 standard.
Once successful testing is complete, application for formal certification can be made to the ABA directly via your supplier of biodegradable products. In turn the ABA has enlisted an independent third party testing laboratory (SGS) to evaluate applications. If successful then an invitation is sent by ABA to license the seedling by payment of nominal fee and signing a license agreement. Successful applicants will then be licensed to use the logo along with their unique certification number.
Use of the seedling logo is available for use by both packaging material producers and their customers. The seedling logo can be printed on the finished product (eg. films, injection mouldings and bags) to market the product’s compliance to AS47362. Use of the seedling logo will ultimately help the end consumer, customers and/or municipal authorities to recognise compostable packaging and dispose of it accordingly. Importantly, the seedling logo will communicate the authenticity and independent verification of claims of compliance to AS4736‐2006.
How do I know whether a bioplastic is suitable for my Home Composting System?
The Australian Standard AS 5810-2010 covers Biodegradable Plastics suitable for home composting. For products or packaging to be able to meet the requirements to compost in Home Composting Systems it needs to meet Australian Standard AS 5810-2010
The ABA has developed its own logo to make it easy for consumers to visually identifying products that conform to Australian Standard for home compostability.
What is the Seedling License?
The ABA has launched the ‘seedling logo’ certification system throughout Australia and New Zealand. The seedling logo is used to clearly identify and differentiate packaging materials as biodegradable and compostable. To be certified compostable and carry the seedling logo, suitable biopolymer materials must undergo a stringent test regime outlined by AS4736 and carried out by recognised independent accredited laboratories to the AS4736 standard.
Once successful testing is complete, application for formal certification can be made to the ABA directly via your supplier of biodegradable products. In turn the ABA has enlisted an independent third party testing laboratory (SGS) to evaluate applications. Successful applicants will then be licensed to use the logo along with their unique certification number.
Therefore, the seedling logo is a symbol that the product’s claims of biodegradability and compostability as per AS4736 have indeed been verified.
The difference between compostable and oxo-degradable
According to the ABA, products that do not meet the standards of Bioplastcs, but only to ‘test methods’ for example, such as the oxos, almost certainly do not and will not biodegrade in a composting facility in any desired time frame.
Bioplastics are a family of products that are biodegradable, biobased or both.
Biodegradability can be confirmed by certification to various internationally recognised standards such as EN 13432, ASTM D6400, or in Australia, AS 4736-2006, where biodegradability in industrial composting facilities is desired. Biodegradability is not affected by the source of the raw material, so fossil-based raw materials can be biodegradable as can some renewable raw materials. These materials, once having passed the standards-required level of testing are certified compostable and therefore biodegradable.
Biobased refers to renewable raw material content in the material or product. For example, biobased-polyethylene (Bio-PE) can be produced from sugar cane, but it is not biodegradable and certainly not compostable. This material is not designed to end its functional life in composting.
The science behind the argument
In the global market today, there are many offerings of derivative plastics claiming to be biodegradable such as those termed by their proponents as oxo-degradable or oxo-biodegradable. These materials are not and probably never will be certified compostable according to the internationally recognised standards.
Biodegradation requires consumption by microorganisms, such as in industrial composting or home composting, but time, heat and other critical factors that affect the biodegradation and disintegration of the product or material, are measured against a performance standard [such as Australian Standard AS 4736-2006 (amendment 1, 2009), referred to above and Australian Standard AS 5810-2010 for products designed for home composting] with pass or fail criteria, as prescribed by the relevant standard.
Terms such as ‘oxo’, ‘hydro’, ‘chemo’ and ‘photo’ describe potential abiotic (non-biological process) mechanisms of degradation. They do not constitute or represent ‘biodegradability’ − the biological process by which microorganisms present in the disposal environment assimilate/utilise carbon substrates as food for their life processes.
Because it is an end of life option, and harnesses microorganisms present in the selected disposal environment, one must clearly identify the ‘disposal environment’ when discussing or reporting the biodegradability of a product, e.g., biodegradability in a composting environment (compostable plastic), biodegradability in a soil environment, biodegradability under anaerobic conditions (in an anaerobic digester environment or even a landfill environment) or biodegradability in a marine environment.
Reporting the time to complete biodegradation or more specifically the time required for the complete microbial assimilation of the plastic, in the selected disposal environment, is an essential requirement − so stating that a plastic will eventually biodegrade based on data showing an initial 10−20% biodegradability is not acceptable and is misleading, especially since the percentage biodegradation levels off and reaches a plateau after the initial rate and level of biodegradation − drawing a dotted line extrapolation from the initial rate and value to 100% biodegradation is scientifically untenable.
Specification standards with specific pass/fail criteria exist only for biodegradability in composting conditions − compostable plastics. There are a number of standard test methods for conducting, measuring and reporting biodegradability; however, they do not have pass/fail criteria associated with it. Therefore, an unqualified claim of biodegradability using a standard test method is misleading unless the biodegradability claim is qualified by the rate and extent of biodegradation in the test environment, and validated by an independent third-party laboratory using internationally adopted standard test methods.
Claims of degradable, partially biodegradable or eventually biodegradable are not acceptable, because it has been shown that these degraded fragments absorb toxins present in the environment, concentrating them and transporting them up the food chain.