Breaking down barriers

There is a great deal of complex science involved in how quickly polymers begin to break down, under what circumstances and conditions of heat, light and air exposure, and indeed whether they actually do at all, once freed into the real-world environment. A point to be clear about is that biodegradable plastics are not necessarily bioplastics – polymer materials produced from biomass obtained from plant matter such as sugar cane, corn starch or cellulose – which can be biodegradable, if made with that end-of-life solution in mind. For the unknowing consumer, this will no doubt be an initial source of confusion.

The term ‘biodegradable’ depicts, according to industry body European Bioplastics: “A chemical process during which micro-organisms that are available in the environment convert materials into natural substances such as water, carbon dioxide and compost (artificial additives are not needed).”

The EU 94/62/EC directive on packaging and packaging waste, section 3(d) in Annex II (Essential requirements on the composition, and the reusable and recoverable, including recyclable, nature of packaging) of Article 3 defines that: “Biodegradable packaging waste shall be of such a nature that it is capable of undergoing physical, chemical, thermal or biological decomposition such that most of the finished compost ultimately decomposes into carbon dioxide, biomass and water.”

However, biodegradable does not equal ‘compostable’. This is a separately defined process, governed by standards such as the European EN 13432, only one requirement of which is that proof must be made that at least 90% of the organic material involved is converted into CO2 within six months.

Biodegradable materials, then, can be composted, depending on the surrounding environmental conditions, on the material and on the application; or a process of biodegradation can lead to composting being possible; or neither may be the case. It is a very complicated area.

Meaningful statements

Such complications are currently a central concern of the European Bioplastics organisation. In the general guidelines section of its new Environmental Communications Guide on Bioplastics, due to be published in September and subtitled ‘Accountability is key’, European Bioplastics sets out that manufacturers should “make specific, measurable and subsequently verifiable claims”, while being “accurate, relevant and truthful”.

With specific reference to claims on biodegradability and/or compostability, and citing ISO 14021, the guide goes on: “Biodegradability as a sole claim without a standard specification is misleading.

“If a material or product is advertised as biodegradable, further information on the timeframe, the level of biodegradation, and the surrounding conditions should be provided. Moreover, data for verification should be made available to interested parties.”

European Bioplastics head of communications Kristy-Barbara Lange adds: “We suggest being as specific as you can. Write information as detailed as possible about what consumers can do with [used packaging materials]. It’s important that it’s well worded throughout the supply chain.”

With all bioplastics currently representing less than 1% of the market, Lange describes biodegradable plastics as “a growing niche”. Common usages include shopping bags and fruit and vegetables packaging, as well as in plastics agricultural sheeting to be buried after use.

“Also, we are trying to substitute materials such as PE, PP, PET and PVC – the mass products where we need new solutions. The goal now is to define one’s solutions, not to substitute everything.”

Opposing camps

“The key to understanding biodegradable plastics is that there are two very different products,” says Michael Stephen, deputy chairman of Symphony Environmental, producer of pro-degradant additive d2w. Hydro-biodegradables (starch-based but often blended with oil-based material) require moisture to degrade. Oxo-biodegradables, however, require the presence of oxygen to allow the additive such as d2w (in oil-based plastics) to do its work in breaking down the molecular structure of the material (beginning at a point in time pre-determined at manufacture), through a process of oxidation, to a point where what remains is no longer a plastics as such, and can be consumed by bacteria and fungi in the environment.

Tellingly, Stephen, whose company is in the ‘oxo’ camp, says: “The two types of biodegradable plastics are very much in competition with each other.”

Hydro-biodegradables can break down in a commercial composting facility, or in landfill. However, once buried in landfill, if the degradation process takes place anaerobically, hydro-biodegradable plastics have been shown to produce methane, given the right conditions such as moisture levels – undesirable in the majority of cases, where the landfill is not set up to deal with this – although European Bioplastics does point to other studies said to show that this is not the case.

Oxo-biodegradables “do not emit any significant amounts of methane” (Oxo-Biodegradable Plastics Association: see www.biodeg.org), and the residues become inert once they get into anaerobic conditions. Hence, Symphony has pitched its d2w additive as a means of dealing with the issue of plastics loose in the environment – essentially litter.

“People want oxo-biodegradable plastics because they don’t like plastics lying around for decades, or hundreds of years,” says Michael Stephen. “That’s the point of oxo-biodegradables.”

Stephen also asserts that d2w has been tested according to British Standard 8472 and OECD standards 207/208, and “shown to be non-toxic”, containing “entirely natural components that are harmless” such as salts of manganese, and “none of the heavy metals”.

In May this year, Symphony announced the results of a life cycle analysis it commissioned from the Intertek Group, comparing Symphony’s d2w oxo-biodegradable plastics carrier bags and bread bags with conventional and bio-based plastics bags. Intertek had prepared an LCA for the UK Environment Agency in 2011, but it did not include the effects of litter.

Commenting on the new report, Symphony’s CEO Michael Laurier said: “While only 0.75% of plastics carrier bags enter the litter stream each year, this amounts to over 48 million bags in the UK alone as estimated in this LCA. The LCA confirms that oxo-biodegradable plastics offers real environmental benefits.”

Among its key findings, the new LCA stated that the oxo-biodegradable bag “performed 75% better than the conventional bag in the litter category”; while “in all other categories the oxo-biodegradable and conventional bags were almost the same”. The bio-based bag was reported to show “the worst performance in 10 of the 11 environmental impact categories”. And the bio-based bag was “superior to the conventional bag in only the litter-effects category, but inferior to the oxo-biodegradable bag even in that category”.

The LCA, Symphony says, noted that “carrier bags are often re-used and should not be described as single-use bags”, and that “bio-based plastics cannot be recycled with conventional plastics in a mixed, post-consumer waste stream without compromising the recycling process, but oxo-biodegradable plastics can be recycled”. In this respect, Symphony says that for long-life products stabilisers can be added to mixed recyclate, and: “Oxo-biodegradation doesn’t function beyond a certain thickness, so if mixed recycled material is used for example in traffic cones, there is no problem.”

However, a five-page Position Paper published by European Bioplastics (in the ‘hydro’ camp, representing over 80 member companies throughout the EU) in July, commenting on the Intertek study, takes the LCA results to task on many levels. The study is described as “unbalanced” and the authors “unaware of the many other studies that show completely different evidence”.

Specifically, the basic premise of the Intertek study is also questioned by European Bioplastics: “A brand-new impact category has even been invented: ‘littering’. However, no standard test method is described and, therefore, any conclusion is arbitrary and based on unverified assumptions,” the paper says.

In the end, each ‘side’ of this vehemently ongoing debate has its plus-points and potential downsides, and it must be up to individual parties in the packaging industry to decide on the available data which solution best suits any application – most likely dependent upon local or regional priorities on end-of-life solutions, carbon tax levels and so on.

Moving forward

As the debate rages, some are already beginning to talk of the ‘next generation’. While Colin Farrant’s company CFM acts primarily as a UK machinery agent in converting and packaging equipment, it also deals in an anaerobic additive from ECM Biofilms and a resin replacement material from ESP Solutions in Canada.

Based on a renewable bio-marine waste source, the ESP303D resin replaces petroleum-based raw materials. Describing it as “a fourth generation product after PLA, oxo-biodegradable and anaerobic additives”, Farrant says that since it is not from an agro land-based source, ESP303D is “not in competition with food production potential”.

“The resin replacement goes in at a much higher level of about 30%,” he says. “It will compost, it will biodegrade, but really where we pitch it is that it’s cost neutral; it will also reduce the amount of petrochemical resin you use, so you’re saving on your carbon footprint; and it’s price-stable, so you’re not trying to continuously follow the mainly upwards fluctuations of oil-based products.”

As a relatively new product, and compatible with most plastics materials used in plastics packaging, Farrant says ESP303D has been “quite well received”. But, he says: “With all these products, sometimes you do need to adapt a process a little – you need to have the will to make it work.”

Farrant believes the public wants to know something is being done about plastics waste, but they don’t know what it should be. “The industry needs to be doing something,” he says. “Each solution has its pros and cons, but for goodness sake, communicate with your customers to improve our image, and improve our environment.

“The best thing is,” he says, “as the Government is trying to get us to do, ‘reduce, reuse, recycle’.”

Biodegradables – news

Showa Denko (SDK) has started commercial-scale production of its biodegradable polyester resin brand Bionolle at its Tatsuno plant in Hyogo, Japan. With its main applications in mulching films and compost bags, Bionolle uses only succinic acid made from starches or sugars, and about 50% of the main raw materials used are now bio-derived, the company says. For SDK’s Bionolle Starcla, in which starch is mixed with Bionolle and PLA, the ratio can be increased to about 70%. The new product has obtained the ‘OK Compost’ mark from Belgium’s AIB-Vincotte (AVI), and is already being test marketed to some of SDK’s customers, notably Natur-Tec in the US.

Germany-based organic tea, coffee and herb producer Lebensbaum has selected a biodegradable and compostable cellulose-based material, NatureFlex NVR from Innovia Films, to pack its range of organic teas. First launched in 2008, NatureFlex NVR is a two-side coated, heatsealable, renewable and certified compostable film with an intermediate moisture barrier, said to be ideally suited to box overwrap and individual flow wrap applications. “NatureFlex films offer both suitable aroma barrier and a functional barrier to mineral oil migration,” says sales account manager Joachim Janz.

“Recent German publications have highlighted that various tea products have weaknesses concerning mineral oil protection,” adds Janz.

French farming concern LCI (Limagrain Céréales Ingrédients) says it has launched the first fully biodegradable and compostable cement bag, conforming to EN 13432, into the French market. BioSac was developed by LCI with Mondi Group, Groupe Barbier and Ciments Calcia, utilising LCI’s Biolice bioplastics film to replace the layer of PE film normally used between layers of kraft paper in cement bags. Nathalie Gorce, marketing manager for Biolice at LCI, says: “Biolice is made using a process unique on the bioplastics market, using whole cereal grains from a number of specific Limagrain maize varieties. The product’s innovation lies in the combination of cereal fractions with a biodegradable polymer.”

Two of Italy-based Novamont’s processing partners, Ecozema and SEDA, produced cups, lids, straws and cutlery using the company’s Mater-Bi family of biodegradable and compostable bioplastics to supply London Bio Packaging and two key sponsors at the London Olympic Games with food packaging at catering services throughout the event’s venues. LOCOG, the London Olympic and Paralympic Games Organising Committee, set an objective that 70% of the waste produced by the Olympics – expected to include 3,300 tonnes of food and food related packaging waste – should go for recycling, re-use or composting.

Polylactide polymer Ingeo, produced by US-based NatureWorks from 100% annually renewable plant-based material, is certified to the ASTM D6400 and EN 13432 standards for composting in municipal and commercial composting facilities. Director of corporate communications and public affairs Steve Davies says: “Composting of Ingeo biopolymer-based packaging and foodservice ware only makes environmental sense when food contaminated plastics diverts food waste from landfills.

“For non-food contaminated polymer- and fiber-based products, chemical or mechanical recycling into new value-added products is the optimum means of diversion from landfills. This leads to cradle-to-cradle scenarios which most experts agree is the ideal for sustainability.”