Top Editors ... The evolution of bioplastics

Title: The evolution of bioplastics
Date: 29/03/2009
Autor: Claire Rowan – Managing Editor

DuPont Packaging has introduced Biomax Thermal 300, a proprietary heat-stabilising modifier that allows PLA thermoformed packaging to withstand temperatures of up to 95°C

Global interest in bioplastics continues as developments in technology bring greater performance capabilities, and investments in the end-of-life handling solutions help support the environmental credentials of this packaging option
According to the European Bioplastics association, bioplastics are a family of polymer products that can be defined as plastics derived from renewable resources and/or biodegradable polymers that meet all the scientific criteria for biodegradability and compostability (in EN13432/EN14995). Therefore, according to this definition, to be known as bioplastics, products that are derived from renewable resources do not necessarily have to be biodegradable or compostable, nor do those polymers that are biodegradable or compostable have to be derived from renewable materials in order to be considered as bioplastics under the EN13432/EN14995 criteria.
As a result, there is a wide choice of bioplastic options on the market. Even many synthetic polymers can be certified as biodegradable, which distinguishes them from conventional plastics that are universally neither biodegradable nor compostable (eg. polyolefins such as PE, PP, PS, PET or PVC), according to European Bioplastics.
“Bioplastics offer in principle all the recovery and end-of-life options that are also in place for conventional plastics. In addition, those compostable bioplastic products that fulfill the EN13432 or 14995 standard are suitable for composting and can be organically recycled as defined by the EU Packaging and Packaging Waste Directive 94/62/EC (amended in 2004/12/EC). This includes aerobic treatment (composting) or anaerobic treatment (biogasification),” said Harald Kaeb, chairman of the board of European Bioplastics. “Home composting as well as industrial composting are well established in most European countries and in some countries nationwide systems exist.”
As all organic household waste must eventually be diverted from landfill, according to the EU Waste Framework Directive, this composting and anaerobic treatment infrastructure is likely to grow significantly in Europe in the future.
However, Leo Docherty, director marketing – Cryovac Food Solutions EMEA, at Sealed Air, which supplies packaging films and machines to the food industry, believes that interest in bioplastics and compostable materials has dropped off over the past year. “What our customers are increasingly asking for is weight reduction and recyclable materials. In four to five years, no-one will accept packaging that doesn’t have an ‘end of life’ solution.” Mr Docherty also highlighted difficulties with the disposal of biodegradable and compostable materials: “Not many people are willing to home compost, and there are very few industrial composting facilities, and no collection infrastructure. The same is true of biodegradable plastics, which only degrade if conditions are right,” he said.
Nevertheless, Sealed Air is actively researching biodegradable plastics, especially PLA and potato starch-based materials. “The main challenge is that these materials do not have good water resistance. We supply packaging mainly for protein products such as meat, fish and cheese. PLA may be suitable for low moisture products such as baked goods, and we are looking into this. Another drawback is that PLA cannot be heated in a conventional oven. It could be suitable for microwaveable foods, and as Sealed Air Cryovac has a lot of knowledge about how microwaves work, that might be an area for development.”
“It must be kept in mind that bioplastic applications cover many different products with widely varying specific compositions and product requirements. The choice of the best is dependent on many factors such as the character of the product, market volume, existing infrastructure for collection and recovery, legislation, and last but not least, costs”, said Mr Kaeb. “These factors can differ greatly from region to region and from one application to another. All bioplastics, including PLA, offer a huge potential for further improvement, and the marketing and use of bioplastics has only just started. In the future, for example, different types (grades) of PLA from a range
of producers could and most probably will have widely varying properties, e.g. the glass transition temperature may range from 60 to above 150ºC. We see enough applications that are ready for market today and there will be many more in a few years.”
To this end, DuPont Packaging has recently announced the expansion of its DuPont Biomax packaging offerings to include renewably sourced Biomax Thermal 300, a proprietary heat-stabilising modifier that allows PLA thermoformed packaging to withstand elevated temperatures during transport, storage and use, which extends its use beyond chilled storage packaging. Biomax Thermal 300 is a U.S. Food and Drug Administration-compliant polymer modifier that increases the dimensional stability of PLA packaging materials to temperatures of up to 95°C when used at recommended levels (between 2 and 4% by weight) and in two-stage forming processes. This is far above temperatures that packages could previously be exposed to during storage and shipping, and the addition of Biomax Thermal 300 to PLA at low levels has also been demonstrated to have a minimal impact on the material’s clarity. The product contains 50% renewably sourced content by weight.
“Because it is bio-based, PLA has strong appeal in food packaging such as produce clamshells and deli trays,” said Susan Homan, North American global marketing manager for sustainable materials, DuPont Packaging, which has launched Biomax Thermal in the USA initially, and plans rollout to Europe and Asia early in 2009.
“However, due to its tendency to deform at temperatures of 55°C and above, its adoption to date has been largely restricted to the packaging of chilled food and beverages. By offering a modifier that raises the working temperature of PLA, DuPont hopes to enable a broader range of applications for the material.”
Innovations Many developments have been seen in the area of bread and dry products. Alcan Packaging has developed and
launched what it claims is Europe’s first fully compostable printed laminate packaging, which has been introduced by UK-based cereal manufacturer Jordans Cereals for packaging its new look Organic range.
“This laminate is ideal for food packaging as it offers both on-shelf appeal and barrier properties, ensuring product protection and integrity as well as food freshness and preservation,” said Rachel Kerr of Jordans about the product, which is the result of three years’ development work. The pack is made using two different certified compostable films: the outer layer is cellulose derived from wood pulp and the inner layer is derived from GM-free corn starch. It has the same look and feel as a heavyweight plastic film, with a glossy, printable surface, and is fully compostable and suitable for degrading on a home compost heap.
Two chocolate companies have selected biodegradable packaging material from Innovia Films for their new ranges.
NatureFlex films are cellulose based, derived from renewable wood pulp and are certified to both the EU EN13432 and the US ASTM D64000 standards for compostable packaging.
“We chose NatureFlex for the packaging of our chocolate bars because it is a non- GM, wood-based product that is home compostable,” said Shawn Askinosie, the owner of Askinosie Chocolate in Missouri, USA. “Our company has implemented vertical sustainability throughout our business practices with everything from the way we source our cocoa beans and our profit sharing programme with our farmers, to the products we produce and sell.”
The 85g and 1kg chocolate bars are wrapped in transparent NatureFlex 120 NVS high gloss film, with enhanced transparency that has inherent anti-static properties. It is semi-permeable to moisture, has a good barrier to gases and aromas, and has good anti-mist characteristics.
Superfood Snacks has selected Innovia’s NatureFlex NM cellulose-based, metallised film. Suitable for home composting – as the level of metal is less than 0.02% – the film has high barrier properties that ensure that
Superfood Snacks’ Chocolate Goji Treats products, which include Goji berries, raw cacao, maca root and sundried vanilla beans, remain in premium condition. It is said to have a high moisture barrier with a transmission
rate of less than 10g/m2/day at 30ºC.
These and other developments taking place in the market will help to increase the awareness of bioplastics. This will in turn encourage increased investment in the technology and the end-of-life infrastructures necessary to improve the viability of bioplastics in the long term.