Thin wall plastics for packaging reduction targets

The Coopbox Group is based in Italy and has over 30 years of experience in packaging for fresh foodstuffs, with a network extending across Europe. Many of the company’s customers have set sustainability targets like Groupe Casino, a major supermarket chain in France, and it is looking at improving the environmental footprint of its products. For example, it has been examining bioplastics, but the price, availability and performance cannot meet every requirement. An alternative innovation is to reduce weight and this has been achieved in its expanded polystyrene (EPS) packaging trays, which weigh 50% less than conventional rigid plastics and its C-PET foamed trays, which weigh 30% less.

Compostable plastics, defined according to EN 13432 (ASTM D6400), are compounded and supplied by FKuR Kunststoff for injection moulding (polylactic acid (PLA) and cellulose acetate (CA)) and thermoforming (CA). PLA has drawbacks due to brittleness (also noisy) and limited resistance to hydrolysis, however additives can improve performance. Biograde V0291 gives clarity in injection moulding with wall thickness down to 0.35mm, while Bio-Flex S 5630 can be thermoformed on conventional equipment with cycle time similar to PP.

Superfos is a leading injection moulder of plastics packaging in Europe producing 2,700 containers per minute at nine locations. It has an active development division, which has looked at consumer trends include snacking replacing conventional mealtimes and the need to maintain nutrition in a busy schedule. The new Superlight range uses 20% less virgin material, has an even wall thickness even down to 330 microns and a stacking rim of only 8 mm. The Superlock range was developed as a glass jar replacement with a 2-year shelf life, maximum reduction in oxygen transmission rate, potential for pasteurisation and sealing before lidding.

From Spain, EDV Packaging has produced a glass-replacement product with PP layers, a tie adhesive and a barrier layer of ethylene-vinyl alcohol (EVOH). This has uses for baby foods, vegetables and pickles, fruit, pasteurised and sterilised products, sauces and pates. New product launches are now trending towards plastics. Waldorf Technik supplies ancillary equipment to assist barrier injection moulding container production, which can include silicon oxide coatings.

Coinjection multilayer moulding is one of the production technologies used to produce barrier packaging with shelf-life of two years i.e. as can and jar replacement. It also offers good clarity, more flexibility for colour, shape (e.g. round, rectangular and oval) and IML. Kortec supplies turnkey equipment and has developed PP/EVOH barrier systems since 2008. One sample container has 3% EVOH and PP walls, and is retortable to 121C. A 32-cavity multilayer moulding system is estimated to produce packaging for half the price of aluminium or steel cans.

EVAL Europe (part of the Kuraray Group of Japan) provides EVOH barrier materials and has examined the oxygen transmission rate after the retort process for different content of ethylene, different times and different film thickness. It has developed a new oxygen scavenging system specifically for transparent retort applications.