By Sean Smyth, Print and Packaging Analyst
Sustainability is a critical factor for all businesses, as we grow to understand the impact humans are having on our planet. Flexible packaging is coming in for more than its fair share of criticism, largely due to the well-publicised issues of plastic waste. Despite these concerns flexibles offer very good environmental performance, with ever lighter weight and energy consumption combining with efficient space utilisation during transport from filling to store and in storage. As recycling methods develop there will greater availability of collection for recycling, even for complex multi-layer constructions, key to boost the sustainability of flexible packaging.
The majority of flexibles are printed on wide web flexo presses that generally use solvent based inks. In North America and most of Europe pollution control systems are widely used as an extension of the press drier. They either recover solvent that is recycled at the ink companies, or incinerate the material released in drying. Even this has an impact on the surroundings, as carbon dioxide is a by-product of burning. There are usually associated odours in the pressroom and escape of volatile organic compounds during printing and cleaning operations despite the use of extraction systems. The ink storage must be managed to minimise the risk of explosion and fire.
This combination of plastic waste and potential VOC or CO2 emissions put flexibles firmly in the spotlight of environmental activists, with pressure to minimise their impact. It is also a significant factor for brands and retailers when they decide their packaging strategies. Large brands are realising their corporate social responsibility is an important source of competitive advantage, as more report their Carbon footprint and actions they take to reduce their environmental impact. The small “Upstart” artisan brands are keen to use innovative packaging, taking advantage of clear panels allowing consumers to see the product while providing maximum convenience. For example, in North America the rise of granola, packaged in stand-up pouches has pressured the whole cereal and dried food sector to change from the traditional cartons to bags and re-sealable pouches to maintain customer appeal.
These brands usually highlight their environmental credentials as a competitive advantage. A strong trend in 2019 is for more consumers to value locally produced items, with low food miles an important factor in choosing which product to buy. Increasingly small and large brands are focusing on reducing their environmental impact, and as packaging can be a major contributor.
One way is for converters to move away from solvent inks. There is a move toward water based functional coatings, but the take up of aqueous inks remains low as these perform differently on-press, meaning press crews have to change their established routines to maintain productivity. Water based inks also require a lot of energy to dry, particularly when printing onto non-absorbent filmic substrates. In changing the company will also need to test the performance in subsequent lamination and conversion.
An alternative way to reduce the environmental impact at printing stage is to use offset litho, with energy efficient radiation curing. The Contiweb Thallo uses ultraviolet drying. However, some converters prefer to use electron beam curing inks that eliminate the use of photoinitiators. In both cases inks are 100% solids, meaning all of the wet ink is cured on the surface of the substrate. There is no loss through evaporation and the ink remains consistent during printing. Drying is a controlled chemical reaction, a free-radical polymerisation that is initiated by UV radiation of the wet ink or by bombardment with high energy electrons. All of the wet ink components are trapped in the high molecular weight polymers that are produced, with the pigment trapped in the film to deliver optimal colour strength and deep black. Inkmakers can adjust the formulation to provide excellent adhesion, flexibility and toughness, resulting in a fully cured inkfilm that is durable enough for many top printing applications without scratching. Films may be surface printed and coated or reverse printed and laminated immediately after printing, eliminating the requirement for de-gassing so reducing time-to-market. When used with alcohol free fountain solutions the use of VOCs is totally eliminated at the printing stage.
According to Smithers Pira printed flexible packaging will be the fastest growing part of the packaging market over the next five years, at an average CAGR of 3.4% to 2024. The market is moving to provide higher print quality, with faster response and the pressures to deliver a sustainable solution will only increase over the next few years. Moving to use offset litho is a demonstrable way for converters to help reduce the environmental impact of their production operations. It is another reason for companies in flexible packaging to look beyond the traditional flexo or gravure printing. As Tesco rightly point out: “Every little helps”
Dr. Sean Smyth is a print and packaging consultant, both independently and on behalf of Smithers Pira. He is also a trade journalist in the UK and North America. With over 30 years industrial experience, he provides hands-on consultancy, helping companies make money through implementing the appropriate technology for their business. After completing his doctorate in Chemistry he joined the industry as an ink chemist before moving into printing and packaging companies where he held a series of senior technical and managerial roles. He has owned and managed printing and packaging businesses in the UK and been involved in many investment decisions over the years. He regularly speaks and acts as Chair at conferences on printing markets and technology, including Smithers Pira Digital Print for Packaging in the USA and Europe. He edited Digital Labels & Packaging magazine from Whitmar Publications, for whom he acts as Group Technical Editor. Beside his Ph.D. Sean also holds an MBA and is used to providing strategic advice to publishers, packaging and print companies together with suppliers (equipment, consumables and software) across the print, packaging and publishing supply chains.
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