As a non-fossil fuel derived material bioplastics now has the opportunity to go mainstream, according to Daniel Gilliland, business development director of Lowell, Ma. based Tellis, a bioscience material manufacturer of Mirel. He says, “When the price of oil passed US$90 bioplastics began to lose its historical price disadvantage and become a serious consideration for packaging and many other durable applications”While bioplastic may have a competitive cost advantage over conventional fossil-fuel plastics the industry still has to come to grips with issues which stand to hold it back both in terms of public perception and technical performance.
Sustainability has become such a good consumer marketing hook, that there are now many companies attempting to greenwash their products: making very tenuous claims of sustainability or biodegradability. Just because a material is derived from a source other than fossil fuel does not automatically make it either green or sustainable .
One of the largest and most obvious attempts at greenwashing began to surface last year when some US aerosol cans appeared with the slogan ‘Contains no CFCs’ or ‘CFC free’. A redundant claim, of course they contain no CFC gasses: they have been banned by United Nations treaties since the early 1990s when the danger to the environment was thought to be simply the hole in the ozone layer. We now know the environmental problem is a whole lot larger. To claim that a packaging application is biodegradable is actually a dangerously spurious claim unless it can be substantiated and quantified in a realistic manner. After all what could be considered a reasonable timescale for a product to be considered biodegradable? A hundred years or 200 years or a thousand years?
When discussing biodegradable packaging materials, honesty of the claim backed by a certification process must be the yardstick. In order for a product to make a claim to be biodegradable, or compostable, it is reasonable to expect that the material can deliver good quality compost, in an industrial composting unit in a three month time-frame. Otherwise it just isn’t commercially viable in the context of sustainability.
Today, everyone wants everything to be totally pure, many brands using bioplastic want to put a label stating that it is ‘100 per cent compostable’ on the pack, believing that it adds value. They should be very careful about doing so, it could actually result in the erosion of brand value when the consumer deliberately selects the product on the basis of a sustainability claim, happily buries it in the garden compost heap and returns six months later to discover it still looking fresh and new.
Consumers have yet to understand that there are two different types of composting: Common or garden home composting – dig a hole and dump in the vegetable matter, and industrial composting requiring heat and specific enzymes which attack and literally eat the material.
To the consumer ‘composting’ implies total disintegration, and however biodegradable PLA based materials might be a package often contains some additives to improve the functional properties of the material. Unless specific studies have been commissioned to verify claims made it would be wise to steer away from claiming 100 per cent compostability – regardless of how easily it trips off the tongue – keep it simple just use the term ‘compostable’, or better yet ‘No fossil fuels were used in this package’.
An example of a fully compostable package would be Mirel’s PLA based cosmetic case which can be fully dissolved in the ocean in approximately 90 days with no industrial composting process.
According to Daniel Gilliland “Since the material is made by an organic microbe similar to those found in nature, it will biodegrade in a wide range of environments; home composting, it will degrade in soil, microbes naturally resident in the soil will colonise the plastic and consume it. It will also biodegrade in the ocean, some people have trouble with that concept, since the general perception is that biodegradability is similar to dissolving the material in water. “That is not the science behind it. Biodegradables are consumed by microbes.”
A Mirel evaluation study took a 1mm thick cosmetic compact case, (see photo) with all the look, feel and functionality of an up market cosmetic package, and placed it in the sea where it was simply observed. Time lapse photographs taken over the 90 day trial period show that by the end of the test the shiny black bioplastic cosmetic case has almost completely degraded.
Since the degradation process is a microbial function, in a parallel test a duplicate compact was put in a dishwasher and washed through 100 cycles. There was no degradation and the compact remained as shiny and black as it was before the first wash. “The required microbe are not present in tap or dish water in sufficient quantity to trigger a degradation reaction” says Daniel Gilliland.
PLA mix substitutes for plastic cutting CO2 emissions by 52 per cent
An example of just how diverse the product potential, “The Arke Group from Erkrath, Japan is both a material and product manufacturer specialising in PLA”, says Yoshiharu Kitajima, European director . “One of our largest clients is Japanese telecom giant NTT. Using a 30-70 PLA-conventional plastic mix NTT a (working) CD-ROM and jewel-case with no degradation to the playability or data-loss. By substituting a PLA-polycarbonate mix for traditional plastic in a CD-ROM the end of use CO2 emissions in incineration can be reduced by a full 52 per cent. Kitajima says, “We have also made inroads into fashion and fabric design using PLA - towels made as promotion for Kirin Beer intended to last for one year. PLA doesn’t have particularly good ‘wet-strength’ properties, so it can be combined with cotton to give additional absorbency properties yet designed to degrade in one year.” Agricultural sheeting and netting from plastic are both a necessity and the bane of many farmers since they have to be laid and removed during planting and harvesting.
However substituting with a PLA formulation designed to biodegrade with six months the protective netting can be ploughed back into the ground and left to compost. One development is that since PLA is essentially of vegetable origin we have been able to impregnate the nets with Japanese chilli which provides a very effective organic form of pest repellent, both for bugs and insects as well as wild animals such as mice and rats which may venture into the field to graze on a young crop in early spring, or in re-forestation projects, bandaging the saplings with the chilli impregnated nets send deer running without impeding the tree’s growth.