Food packaging varnish development for enhanced gas barrier

The EU-funded SVARNISH project aims to use nanotechnology to improve the oxygen, antimicrobial and moisture barrier properties of currently used food packing. It also aims to reduce the environmental impact and production costs of such packaging by simplifying traditional multilayer structures for easier recycling.

Current work is focus in the reduction of the use of laminated multilayer films (which may be complex to manufacture) with a single varnish formulation that can be easily applied to a variety of substrates. The development of a varnish formulation with a high barrier to oxygen and water will allow shelf-life extension of foods (initially, bakery goods are the target application), reducing food waste and potentially reducing reliance on metallised, multi-layered films for high barrier applications as these are expensive and difficult to recycle.

Component materials selected are based upon safety in use as food packaging additives and for the performance properties provided to the varnish when applied to the film substrate: gas barrier performance is realised by the tortuous path to gas diffusion provided by high aspect ratio platy minerals (organically-modified nanoclays); optimum exfoliation of the clay platelets is achieved by a process of in-situ polymerisation, requiring the incorporation of an organic modifier that is stable at the high temperature involved in the synthesis of the selected polymeric carrier; encapsulated volatile essential oils are investigated for incorporation in the polymer matrix for antimicrobial activity.

A varnish formulation is formulated by dispersing the nanocomposite developed and the essential oil selected and optimised for flexible printing technologies; (flexography and gravure) for food packaging application. This varnish layer would provide enhanced barrier properties usually found in multilayer packaging, while being cheaper to produce and easier to recyclable.

Once the packaging for food quality and safety is evaluated, SVARNISH will test prototypes to determine which foods can be packaged using the new product. Ultimately, SVARNISH's structurally simple and eco-friendly packaging could positively impact the environment through lessened material use and food waste.