Paper Coating |
Paper Coating | Laminating Mater-Bi Innovative Materials For Extrusion Coating and Lamination Aricle contributed by Stefano Facco, New Business Development Manager and Roberto Marangon, New Business Development Application Developer, Novamont SpA, Novara, Italy Compostable bioplastics like Mater-Bi ® , derived from or containing renewable resources, are a new generation of materials able to significantly reduce the environmental impact in terms of energy consumption and green-house effect in specific closed-loop applications (like food packaging, catering items, mulch etc), to perform as traditional plastics when in use, and to completely biodegrade within a composting cycle through the action of living organisms when engineered to be biodegradable. Novamont’s main mission is to offer original solutions both from technical and environmental point of view, starting from renewable raw materials. Mater- Bi is a generation of established compostable polymers, continuously evolving, 24 bioplastics MAGAZINE [06/08] Vol. 3
Paper Coating | Laminating Second substrate First substrate Laminate containing starch and other renewable resources, able to significantly reduce the environmental impact in terms of energy consumption and green-house effect in specific applications, to perform same as or even better than traditional plastics when in use and completely biodegrade within a composting cycle. New sectors are growing in different industrial applications, driven by technical performances as in the case of extrusion coating/lamination. The process of extrusion coating, typically based on standard polyolefines, consists in extruding a thin web through a vertical flat die onto a substrate. The substrate can be paper, board, plastic film, aluminium foil, nonwoven etc. Extrusion lamination is very similar to extrusion coating and requires the same equipment: in this case the molten polymer is used as an adhesive, in order to couple (‘glue’) two substrates. Depending on the application, these converting techniques provide a very efficient and versatile way to build specific, tailor made, multi-layer structures. The development of an ‘industrial’ material for extrusion coating is based on a very challenging, demanding and time consuming research activity. First of all, the converting technique itself is very demanding in terms of technical properties: the main evidence is that nowadays just very few polymers are successfully used. More than 90% of extrusion coating/ lamination is carried out with some very specific ones. Second, (compared to blown film lines or injection moulding machines) extrusion coating/lamination equipments are usually very big and ‘rigid’ lines, designed in order to run 365 days a year with high outputs and efficiency, with unchanged parameters; not an ideal system to carry out trials, both from the technical and economical point of view. On the other side the availability of small and flexible pilot lines is rather limited. The interest of the market for a ‘tailored’, compostable material is very high, and some solutions are popping up and being tested on industrial scale. The interest is even higher considering that lamination with adhesives is right now missing a biodegradable and compostable high performance product. Extrusion coating of Mater-Bi onto paper and cardboard is very attractive because it represents a way to build a fully biodegradable and compostable structure. Theoretically such a product can offer the maximum number of recovery options, by further adding composting though maintaining the repulping option. The main areas of interest are foodservice (cups, plates, bowls…), wrapping paper or folded cardboard for frozen food. Extrusion coating/lamination with biodegradable and compostable films allows to combine specific properties of the single constituents and build multi-layer structures with excellent technical performances and environmental profiles. The availability of compostable moisture barrier rigid substrates (like for instance metallised cellophane and PLA) and extrusion coating resins characterised by excellent adhesion, sealability, toughness and puncture resistance (like Mater-Bi) allows to approach highly technical applications like flexible food packaging. Several applications based on the various existing technologies and substrates are close to be introduced on the market. Mater-Bi has shown to satisfy most of the needs in terms of process, performance and end of life options (compostability, repulpability and others). The possibility to use Mater-Bi in such high performing technology, represents a further tool to better tailor specific products and propose original solutions both from technical and environmental point of view, fulfilling specific in use performances of different application sectors. www.novamont.com bioplastics MAGAZINE [06/08] Vol. 3 25
