Multilayer Packaging Film Advances Discussed at AMI Conference

The new international conference on Multilayer Packaging Films organised by AMI Ltd was attended by delegates from 19 countries across the world. It took place in Cologne, 27-29 March 2007. Andrew Reynolds (AMI) kicked off with a review of the markets for film – PE makes up the bulk in Europe at 54% of demand with ‘other films’ at 46% (of this 58% is BOPP, 11% CPP, 8% BOPET, 8% PVC, 5% PA, 5% EVOH, 2% BOPA, 1% cellophane and 2% miscellaneous materials). Tony Hoare of Rapak described the issues in developing bag-in-box film. This type of packaging is used for wine, post mix, aseptic, dairy and ingredient packaging and ranges in size from 0.75 to 1400 litres. Typically there are two layers with an outer layer such as PET/EVOH/PA and an inner layer of a material such as LLDPE. It must look good, meet standards, consider waste recovery and not taint the product. Pactiv described a range of advanced closure systems including resealable pouches and gave an excellent overview of the issues of making packaging easy to open, plus the technology of filling different types of packaging. Pradeep Tyle (Flex Industries) reported on the production of metallised films and areas of growth such as replacement of aluminium foil. Keller and Heckman examined EU regulations and food contact issues for multi-material packaging which often contains a mix of plastics, metal, coatings, adhesives, inks, cellulose and paper. Fraunhofer IVV has studied permeability of different kinds of materials and methods of predicting the permeability of a multilayer film. Borealis introduced multimodal LLDPE produced with a two-reactor system, which can be processed on multilayer film lines and has a balance of toughness and high impact strength. Topas Advanced Polymers has cyclic olefin copolymers which are glass-clear, resistant to acids and polar solvents, low extractables and high purity with wide regulatory approvals. DSM described PA6 for food packaging – oxygen barrier, aroma and flavour barrier, puncture resistance, thermoformability, etc. In one multilayer film for meat packaging, the polymer make up was PP/tie layer/PA/EVOH/PA/tie layer/PE. Nanocor gave a presentation on the use of their nylon MXD6 nanocomposite barrier materials. DuPont discussed ways to cut costs while enhancing packaging performance using factors such as smart downgauging with their ionomer resins. Basell has seal-peel technology developed by using polybutylene to modify the properties of PP and PE: the dispersed PB assists the peeling of the seal. Rohm and Haas has adhesives and coatings for the multilayer film market and described the EU and FDA regulations, curing of adhesives for retort pouches and retort testing. Windmöller and Hölscher presented information on blown multilayer film technology and showed a variety of multilayer films, for example a 9-layer film of: PE1/PE2/tie layer/PA/EVOH/PA/tie layer/PE2/EVA. Extrusion Dies Industries followed this up with a discussion of die design to cover factors such as minimising EVOH and PA contact with metal surfaces by streamlining the flow path. Gruppo Colines has developed cast film lines up to 7-layers with thickness of 30-300 microns. These barrier films are mainly used in medical and food packaging applications. One example of a film used in thermoforming consists of: PP/tie layer/PA/EVOH/PA/tie layer/PE and is used in meat packaging. Enercon talked about surface pre-treatments for films – polyolefins are often very inert and if the surface can be activated it aids adhesion in post-extrusion processes such as printing, lamination or coating. NDC described methods of gauging film for quality control using infrared sensors, and the ability to measure individual layers in co-extruded films. The conference was very successful with a lot of positive feedback, so AMI is scheduling the next Multilayer Packaging Films conference for 28-30 October 2008 at the Maritim Hotel in Cologne, Germany – offers of papers should be sent to Dr Sally Humphreys