Biodegradable, Degradable & Compostable Packaging Explained

Board paper and plastic packaging all have the same requirement for compostable certification under European standard EN 13432:2000 recognisable by the seedling logo. Paragon Print and Packaging have attained EN 13432:2000 for the Labels, Sleeves and Film.

We will concentrate on plastics for the purpose of our explanation because there are some exciting new technologies emerging in this field.

Biodegradable plastic will degrade as a result of bacterial activity. In order to also be classified compostable, ther degration must meet certain specified criteria such as rate biodegration, maximum residue of material left a a specific point in time as a requirement for the material to have no harmful impact on the final compost or the composting process. All compostable plastic is therefore also biodegradable. The standard for compostable plastic used is the European standard EN 13432.

Degradable plastics are not compostable. Most of the products using the label Degradable plastic, degrade as a result of physical and chemical impact (fracture into smaller pieces of plastic). They are oil based products with special additives that assist their 'fragmentation'. Biological activity is not a significant part of the degradation of these products, or the process is too slow to earn the classification Biodegradable or Compostable (the Biological degredation will typically take many years).

Bioplastics are a new generation of biodegradable and compostable plastics, derived from renewable raw materials such as starch (e.g. corn, potato, tapioca etc), cellulose, soy protein, lactic acid, etc, not hazardous in production and decompose back into carbon dioxide, water, biomass etc, in the environment when discarded. Corn starch is currently the main raw material being used in the manufacture of bioplastic resins. Mater-Bi (main componenet corn-starch), and PolyActide (PLA) (made from corn-starch as well) are currently the 2 main resins (raw materials), being used today in the production of compostable and biodegradable plastics and are certified for compostability under standards soybean protein, cellulose etc. Most of these are currently not certificed for compostability, though some are for biodegradability. The field of bioplastics is constantly evolving with new materials and technologies being worked on and being brought to market.

Heat Resistance
Corn-starch based products (bags, corn cutlery, cold cups, drinking straws) 120 degrees F Potato and tapioca starch based products footato cutlery) 220 degrees F. Biodegradability & Compostability
Bioplastics can take different length oftimes to totally compost, based on the material and are meant to be cornposted in a commercial com posting facility, where higher com posting temperatures can be reached and is between 90-180 days. Most existing international standards require biodegradation of 60% within 180 days along with certain other criteria for the resin or product to be called compostable. It is also important to make the distinction between degradable vs. biodegradable vs. compostable as often these terns are used interchangeably.

Compostable Plastic is plastic which is "capable of undergoing biological decomposition in a compost srte as part of an available program, such that the plastic is not visually distinguishable and breaks down to carbon dioxide, water, inorganic compounds, and biomass, at a rate consistent wrth known compostable materials (e.g. cellulose), and leaves no toxic residue." American Society for Testing & Materials (ASTM).

In order for a plastic to be called compostable, three criteria need to be met:

• Biodegrade - break down into carbon dioxide, water, biomass at the same rate as cellulose (paper).
• Disintegrate - the material is indistinguishable in the compost, that it is not visible and needs to be screened out.
• Eco-toxicity - the biodegradation doesn't produce any toxic material and the compost can support plant growth.

Biodegradable Plastic is plastic which will degrade from the action of naturally occurring micro organism, such as bacteria, fungi etc. over a period of time. Note, that there is no requirement for leaving "no toxic residue", and as well as no requirement for the time it needs to take to biodegrade.

Degradable Plastic is plastic which will undergo a significant change in its chemical structure under specific environmental conditions resulting in a loss of some properties. Please note that there is no requirement that the plastic has to degrade from the action of "naturally occurring microorganism" or any ofthe other criteria required for compostable plastics.

A plastic therefore may be degradable but not biodegradable or it may be biodegradable but not compostable (that is, it breaks down too slowly to be called compostable or leaves toxic residue).

Standards
There are currently few international organizations which have established standards and testing methods for compostability, namely:

• American Society for Testing and Materials ASTM-6400-99
• European Standardisation Committee (CEN) EN 1 3432
• International Standards Organisation (150) I S 0 14855 (only for biodegradation)
• German Institute for Standardization (DIN) Dl N V49000

The ASTM, CEN and DIN standards specify the criteria for biodegradation, disintegration and eco-toxicrty for a plastic to be called compostable.

Biodegradabilrty is determined by measuring the amount of C02 produced over a certain time period by the biodegrading plastic. ASTM, IS0 and DIN standards require 60% biodegradation within 180 days. The EN 13432 standard requires 90% biodegradation within 90 days.

Disintegration is measured by sieving the material to determine the biodegraded size and less than 10% should remain on a 2mm screen for most standards.

Eco toxicity is measured by having concentrations of heavy metals below the limits set by the standards and by testing plant growth by mixing the compost with soil in different concentrations and comparing it with controlled compost.

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Punch are the creative division of Paragon Print and Packaging and specialise in image elevation.

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