Biome in the press - Packaging News Thursday, 8th April 2010
MAP film: a fresh direction
Given the sophisticated performance and cost-effectiveness of traditional oil-derived polymers for MAP shrink films, can biopolymers really compete in this market?
Stanelco group company Biome Bioplastics believes so. Having focused its R&D efforts on heat resistance, it is now busy tailoring versions of its biopolymers, principally starch-based, with improved moisture barrier properties.
Thermoplastic starches tend to provide a good gas barrier. The challenge hinges on the tendency of natural starches to absorb water, says Biome. This is one reason why flexible biopolymers have been associated with fresh produce, where the natural transpiration of the material is a benefit.
But while this means that the resin needs to be supplemented to curb these moisture-absorbing tendencies, any adaptation needs to maintain their compostable (or at least biodegradable) character.
As Biome managing director Paul Law says: "You could, cynically, simply fill out the structure with hydrophobic material and still say it was ‘starch-based', but it would no longer be biodegradable."
In fact, a combination of additives and a thin layer of ethylene vinyl alcohol (EVOH) need not break the 5% barrier stipulated in the PAS 2050 compostability standard, he claims.
Of EVOH, Law says: "Although it will keep moisture out, it absorbs moisture, allowing the film to eventually break down." Whether that process is sufficiently fast to allow designation as ‘compostable' remains to be seen, he adds.
R&D work has already yielded a list of potential candidates for barrier combinations, he says. The most promising will undergo independent testing, and a range of solutions should be available by the autumn.
Meat, poultry and other MAP markets have not been associated particularly with bioplastics in the past. But Law points out that demand for biodegradable absorbent pads for this type of pack has increased, making sealing films the next logical step.
Read the full article here.
