The company claims that the new cup lends itself to far more than drinks and has high potential in areas where innovative design and user-friendliness are key objectives.
Made from a special paperboard with high barrier coating, Stora Enso claims that the airtight cups are ideal for snacks, cereals, confectionery, biscuits, tea and regular and instant coffee.
What's more, the company claims that tightness, which is achieved through a combination of specially developed paperboard, heat-sealed raw-edge taping and innovative lid sealing, can be tested and verified with Stora Enso AT Master tightness-testing equipment, based on tracer gas.
This equipment uses hydrogen as a tracer gas, which Stora Enso says is easy and safe, cost-effective and 100 per cent reliable. "In the tracer gas test, the sample cup is filled with a gas compound containing hydrogen and nitrogen, and a detector sensor is used to scan potential leakage points," said Jalliina Järvinen, manager of food solutions at Stora Enso.
"In the detecting station, the tracer gas hydrogen is forced out of the cup in the event of a leak. The results guide fine-tuning of the cup-making process in order to eliminate any defects."
Stora Enso's airtight cup has been designed to provide prolonged shelf-life for packaged food without altering the taste, odour or nutritional value of its contents. With its gas-mixture-modified atmosphere, it keeps the contents safe during long shelf-life, preventing the aromas from evaporating and fats from turning rancid.
The company is also launching its special non-foil paperboard Cupforma AT for the airtight cups at Interpack. The paperboard's water-vapour barrier properties protects the contents against caking, loss of crispiness, mould growth, softening of texture and change in colour, taste and odour.
In addition, the oxygen barrier protects the packaged food against rancidity, loss of vitamins, growth of microbes and oxidation of lipids. Stora Enso's Silver Barr coating provides maximum light, oxygen, humidity and aroma protection for light-sensitive products.
"Raw edge taping is essential to the tightness of the cup's side seam in airtight applications," said Järvinen. "The side seam is sealed and the bottom is attached in heating stations, where optimisation of the heating temperature and the amount of air ensures that the seams become tight and leakage-proof.
"The rim of the cup is flattened to ensure tight sealing of the lid. The lid sealing is conducted with specially-designed heated tools."