High quality laminated structures for flexible packaging are now achievable using solventless adhesives, water-borne inks, and bio-based films and adhesives. That's the result of research and actual production data presented at the Sustainable Packaging: Reducing the Carbon Footprint conference session at Pack Expo Las Vegas.
Representatives from Nordmeccanica, Dow Adhesives, Environmental Inks & Coatings, Innovia Films and Portco Packaging offered their insights on their recent ‘Earth Day’ machinery and material demonstration.
Innovia’s Stewart Richards described the manufacture of the bio-material lamination using bio-based film, inks, adhesives and a bio-based sealant layer. His company’s NatureFlex films contain 96% renewable carbon content and only 4% fossil carbon. The concept was to create a bio-based, food packaging material that can be disposed of in the same stream as food waste to municipal composting sites.
Nancy Smith, of Dow Advanced Materials Division, ran down the choices of solvent-borne solids, water-borne and solventless adhesive options. As part of the Earth Day demo, a Life Cycle Inventory Analysis compared these three adhesive types. The Cradle-to-Gate LCI showed that solventless laminating used only 50 Megajoules of energy versus 150 for water-borne and 250 for solvent-borne adhesive.
Solventless laminating can cut energy consumption by up to 80% versus thermal dried, solvent systems, said Giancarlo Caimmi, of coater/laminator supplier Nordmeccanica. High viscosity solventless adhesive layers are 80 times thinner than a human hair, so process control is very important to get a proper lamination, he added. The equipment needs servodrives, perfect software, low friction bearings and dynamically balanced idler rolls, and extreme tension control.
Rich Castillo, of flexible packaging converter Portco Packaging, said that before the group's work, "There were not many benchmarks available for using a sustainable converting process totally, as we did." Key points to remember, he added, are good plant housekeeping, temperature control, precise meter mixing of adhesives, and achieving your target coatweight across the web.
"The lack of heat is key in solventless laminating to run bio-based packaging films. It's what makes it possible," Mr Castillo emphasised.
Report from Mark Spaulding, Editor, Converting Magazine
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