Wacker's new Vinnacoat LL 8100 surface coating resin allows effective sealing of aluminum foils to non-polar plastics. This makes it particularly suitable for heatsealable packaging systems such as yogurt lids or juice cups.
Vinnacoat LL 8100 is based on a styrene-olefin copolymer with carboxyl functional groups, which confers high toughness and permanent flexibility, heat-sealability to non-polar polymers such as polystyrene, polypropylene and polyethylene - plus outstanding adhesion to metal surfaces such as aluminum.
Until now, acrylate-based binders were predominantly used for heatsealing coated aluminum foils to non-polar polymers. Wacker's new coating offers an alternative.
The thermoplastic binder is said to show very low swelling in the presence of water and high resistance to a wide variety of liquids, from oils and greases, through dilute acids and alkalis, to alcohol and aqueous salt solutions. Thanks to the polymer's inherent elastic properties, no additional plasticizers are generally required in the formulation.
Also new from Wacker is Vinnol H 5/50 A, which has been developed for specifically for printing inks in food packaging. The binder is a vinyl chloride-vinyl acetate-vinyl alcohol-terpolymer containing functional hydroxyl groups. These ensure the surface coating resin adheres strongly to a wide range of polymer substrates and may be crosslinked using a variety of reagents. Its high content of vinyl chloride polymer units is said to provide excellent chemical resistance to the surface coating, while the vinyl acetate units impart high flexibility.
Further useful properties of Vinnol H 5/50 A include high pigment compatibility, rapid resin and pigment dispersion, excellent compatibility with co-binders, as well as high solubility in ketones or in cost-saving ester-based systems.
Coatings based on Vinnol H 5/50 A are waterproof and extremely resistant to oil, grease, dilute acids, alkalis and salt solutions. The coating resin is also both taste and odour-free, and complies with EU and FDA food contact regulations.
