Packaging made of calcium carbonate, or chalk, may sound unlikely but one Swedish company was inspired by the humble egg to use the material to produce an environmentally friendly alternative to plastic and card.
EcoLean, inspired by nature’s use of calcium carbonate to form an egg shell, decided to use the compound in its packaging because it is biodegradable, plentiful and cheap.
The company has combined the chalky substance with a biodegradable plastic to create a new packaging material.
‘We want to package food with the minimum amount of energy and make savings in plastics by continuously increasing the calcium carbonate content. Basically, we’re tackling the problem of distributing food with much less waste of resources,’ said EcoLean’s marketing director Mats Harborn.
The new compound has been named LeanMaterial and is used for products such as drinks bottles, pouches for milk, juice and yoghurt, wrapping film for butter and disposable boxes for the fast food industry.
Franklin Associates, a US-based environmental consultancy says that EcoLean’s technology should result in products with a much reduced environmental impact compared with those made of glass, laminated cardboard, aluminium or plastic.
Apart from being biodegradable, less energy is used in producing LeanMaterial products. The energy required to make a kilogram of packaging from polystyrene is 52MJ. For paper it is 48MJ, and for aluminium foil it is 200MJ. EcoLean claims that the manufacture of LeanMaterial requires just 20MJ/kg.
The chalk, in powder form, is co-extruded with either polypropylene or polyethylene – both of which are recycled in Sweden. LeanMaterial consists of up to 70% chalk but the company wants to increase this to further cut both production costs and the material’s ‘green’ impact.
EcoLean’s direct competitor in the eco-friendly packaging market is US company Earthshell. It uses a composite of calcium carbonate and potato starch in disposable food packaging and supplies McDonald’s with boxes for Big Macs.
Starch-based biodegradable plastics have been on the market for several years. Earlier this year, Sainsbury’s introduced potato-based biodegradable packaging. But EcoLean prefers not to use starch, citing cost and processing problems. (For example, starch is not naturally water-resistant and has to be mixed with other materials.)
But production has not been EcoLean’s only concern, as the company is determined to ensure that the disposal of the packaging should be equally ‘green’.
Many countries are looking at ‘alternative’ methods of waste disposal, some of which involve burning waste to generate power.
It is likely that waste LeanMaterial would be sent for incineration and, for that reason, the composite has a designed energy recovery value of 7MJ/kg. This is the legal minimum requirement set out in a European Union directive for waste that is incinerated to generate power.
On the other hand, landfill disposal would pose a problem. Although LeanMaterial breaks down when exposed to sunlight, the company admits that the product would not degrade in a landfill site.
Harborn said: ‘It would not degrade, but we would be reducing the plastic content of landfill. We can also make the packaging compatible with industrial composting processes which use bacteria and pressure.’
This flexible approach could help to gain approval from government agencies. Permission is needed from national authorities whenever any material is to be used to form food containers.