Compostable packages

Brenmar was one of the first companies to introduce NatureWorks PLA compostable packaging for the food service market. The Versapak product line includes containers for fruit produce and fresh or frozen bakery products. Other Brenmar products include cold drink cups, cutlery, bowls and hinged clamshells. 

J. Reske, "Beauty of Bioplastics. Compostable Packaging Sees a Bright Future Ahead, Waste Management World (March-April 2005). 

Kosior, E., Braganca, R., Fowler, R, Lightweight compostable packaging Literature review, WRAP project, June 2006. 

The state-of-the-art in the field of lightweight compostable packaging has been reviewed (5). The review starts with an overview of compostabdity, biodegradabihty and presents some definitions. A brief summary of the current use of synthetic commodity polymers used in packaging is followed by an analysis of commercially available, renewable polymers. An overview of the technology of production has been presented, as well as existing and emerging producers (5). 

E. Kosior, R.M. Braganca, and P. Fowler, Lightweight compostable packaging Literature review. Project INN003/26, BioComposites Centre, University of Wales, Bangor, Gwynedd, 2006. 

Starch-based foams can provide compostable packaging for the fast-food industry The extruded starch foam can be coated with a outer layer of acetylated starch to provide water resistance, or a foamed starch-acetylated starch hlend can be so coated (76,77). Starch has also been coated with the microbial polyester PHBV to provide resistance to hot and cold water a natural resin, shellac, prevents delamination (78) (Fig. 8). 

Recently, compostable packaging materials were introduced into the market to reduce the amounts of conventional packaging materials and at the same time be recovered by the municipal organic waste collection system. An example of commercial implementation of compostable polymers includes Cargill Dow Nature Works polylactic acid (PLA), which is produced at a rate of 140000 tonnes/year at Blair, Nebraska (USA), via carbohydrate fermentation. Other... 

Generally, renewable raw materials can be used to produce either long-term living products like constmction materials for automobiles, ships and for the building and constmction sector, or short-term living products like compostable packaging or biodegradable mulch films. 

BASF has introduced their aliphatic-aromatic copolyesters (AAC) product under the name Ecoflex . This material is widely used to produce compostable packaging and films. According to the BASF s corporate website, annual production of Ecoflex has risen to 60,000 MT to keep up with the demand for biodegradable plastics, which is growing at a rate of 20% per year. At the same time, BASF also produces a blend of polyester and PLA — a product called Ecovio . This high-melt-strength polyester—PLA can be directly processed on conventionally blown film lines without the incorporation of additives. Moreover, Ecovio has extraordinary puncture-and tear-resistance and weldability. Another company, Eastman, has also produced AAC, with the tradename Eastar Bio . Eastar Bio has a highly linear structure, while Ecoflex contains... 

UK supermarket Sainsbury s announced in October 2006 that 500 of its own-brand goods would be in compostable packaging. 

As an example a PLA film under 20 pm thick is compostable and packaging made and marked with this symbol can be commercially composted. Thicker films above 20 pm although still biodegradable do not qualify as compostable. A home composting logo has yet to be established. However, at some point in the future this will enable consumers to dispose of compostable packaging directly on their own compost heap. At the moment plastics can only be disposed of in industrial compost units. 

Starch could also be foamed by water vapor to make compostable packaging foams [24]. To provide water resistance, acetylated starch, which is a less polar material and more water resistant, could be used as the foaming material [25]. For the same purpose, TPS was also first blended with hydrophobic polymers (e.g., PHBV, PCL, PBS, PVA, and PLA) and subsequently foamed [26-28]. Besides water vapor, CO was also used as the foaming agent in TPS/ PLA foams [29]. 

The hydrolysis of the polymers leads to molecular fragmentation. The hydrolytic degradation of lactic acid based polymers is an undesired phenomenon under certain circumstances, such as during processing or material storage. It is however, beneficial in other applications, for example in medical devices or compostable packages (12). 

On the basis of the mandate M200/ref.3 of the EU-Commission the standard for biodegradable/compostable packaging EN 13432 was elaborated and published as harmonised standard in the Official Journal of the EU. 

According to the EN13432 a packaging is compostable if it is formed by components, which have been, each individually qualified as compostable. In this way the analysis of compostability of a packaging is simplified and traced back to the analysis of compostability of the single constitutive materials. Therefore, it is sufficient to use compostable materials in order to obtain a final compostable packaging. 

The European norm defines the specific properties of the compostable packaging materials and the test methods needed to verify their conformity. The compostable packaging shall be endowed with four main features. 

The maximum concentrations of heavy metals allowed in the compostable packaging are specified by the EN13432. In this case, the limits are lower than those required by the Directive 94/62/EC, because the release of heavy metals in the final compost is highly detrimental for the quality of compost. These limits have been derived by the heavy metal limits allowed in final compost, according to the European Eco-label for soil improvers and considering a mass reduction of 2. 

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