MATERIALS | POUCHES
The company has created a ‘digital pouch
factory’, which combines pre-press, digital printing, lamination, slitting and pouch-making equipment into a single line. This, he said, is an efficient way to produce on-demand flexible packaging. In a recent example, Lithuanian flexible packag- ing converter Printela used HP Indigo’s digital print- ing press – with ‘Pack’N’Cycle’ film from Polysack – to create customised pouches.
Above: Flexpack manufacturer Printela has used HP Indigo’s digital printing press and Polysack film to create customised pouches
lines and assessment via the RecyClass tool leads to a certification ‘score’ – which gives an indication of recyclability. For example, a clear PE pouch will be assessed on multiple factors including collec- tion, sortability and recyclability – leading to an overall result. Di Gregorio presented an example of a PE pouch with a PP cap. It was a multi-layer structure with a 5% EVOH layer, had direct printing with clear colour (4%) and had no labels or other attach- ments. The presence of the PP and EVOH played a role in reducing the ‘recyclability’ to 52%, equiva- lent to a Class C. “Avoid mixing flexibles and rigid components
– or reduce the rigid component weight as much as possible – as it jeopardises the sortability,” he said. In addition, he recommended monomaterials,
and transparent – or colourless – packaging, in order to improve recyclability.
Flexible printing The market for stand-up pouches is growing faster than the flexible packaging sector as a whole, according to Josep Isart, flexible packaging business manager for EMEA at HP Indigo in Spain. He told delegates that the global market for stand-up pouches is expected to grow by nearly 8% each year to 2026, reaching a value of US$20 billion.
In this time, he said, the market will begin to
adopt ‘digital technologies’ – such as digital printing that allows short-run decoration of products.
He said the digital printing – such as that
provided by HP Indigo – can help smaller packag- ing companies to compete with their larger rivals. Digital printing removes many steps from the printing process, including plate making and other processes. “This helps small to medium businesses disrupt their marketplace by bringing craft brands to life with greater creativity,” he said.
30 FILM & SHEET EXTRUSION | July/August 2021
Sealing the deal Digitalisation can also extend to the sealing process, as Marcus Stein, CEO ofWatttron in Germany, explained. This involves using ceramic heaters that are segmented into “hundreds of closed loop circuits” rather than a conventional contact heating plate with a single circuit. This system, called Cera2Seal, allows far more accurate application of heat, he said.
One consequence of this is an increase in
energy efficiency. During the ramp-up process, he said energy efficiency can be increased by 8,000%. This was evidenced by a graph showing the energy needed with a conventional system was around 44kJ – while that with a Cera2Seal system was around 0.5kJ. The heaters are incorporated into digital sealing jaws for both horizontal and vertical form-fill-seal machines. This can be used for mono-PP or PE, in widths of 4 to 15mm The company has also developed a digital
sealing tool for spouts, ports and other elements. It seals the spout and the two-layer area of the pouch in a single step – and has been retrofitted to a multi-station HFFS machine.
Mono-material challenge Recyclability is a key attribute for pouches – but there are many challenges to making mono-materi- al packaging including optics, shrinkage and temperature sensitivity. These are some of the reasons why pouches tend to be made from multiple materials. Martin Hill, application technology leader in
EMEA for food and speciality packaging at Dow, told delegates that pouches need to be designed for both recyclability and machinability. This means finding ways around the challenges of mono-mate- rial packaging. He said that Dow’s Affinity plastomers can help to do this, by improving properties such as sealabil- ity. The resins have low seal initiation temperatures and lower blocking force – allowing film output to be increased by up to 25%, he said.
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IMAGE: POLYSACK
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