Film & Foil


polyester films a popular choice. It is not uncommon now to find that for package applications, one may find that the pack is constructed with several layers of substrate and coatings. For instance, PET may be in the top most outer layer of a beverage pack, below this is the print and primer coating layer followed perhaps by an LDPE (low density polyethylene)/foil layer and a final layer, which is a LDPE/heat seal layer. Packaging technologists and converters


will take a different approach to the one outlined above depending upon circumstances. If the product is a retort pack, the layering may look something like the following: PET/print and an adhesive coating layer/foil/primer coating and LDPE. Although PET made its debut as long ago as the 1950s, further development is on going. Certain grades of PET are being used in areas such as cosmetics and personal care products. In some instances the film is embossed with holographic design. Returning to the polyamide films, further


refinements has resulted in them becoming well know and accepted for high temperature applications. They are noted for their ability to maintain the integrity of di- electric properties, at temperatures as high as 240 C and they are used in coil winding insulation for industrial applications such as the manufacture of motors. For still higher


applications films made from (PEEK) Polyaryletheretherketone are employed. These offer good resistance not only to temperatures in excess of 260°C, but are also resistant to solvent, chemical and even fire and smoke. Mention must be made of the


transparent fluropolymer films and the nylons. The former is widely used in the chemical and in the manufacture of electronics, such as circuit boards. It also features increasingly in the packaging of medical and pharmaceutical products. With regard to nylons, ordinary bi-axially orientated nylon (BONN) is well known. A more exotic version known at Nylon6 is used as a matrix for nano film structures. As mentioned earlier, films, as with other


materials convertibility and printability, are an issue. Converters and consumable providers need to minimise process inconsistencies as much as possible. Films destined for packaging applications must print well and must be manufactured with minimal gauge band variation. Time is also of the essence, process variables must be bought under control and problems rectified as soon as possible. After all the printer, the converter and other producers and suppliers are only earning revenue when a job can be mounted on a machine, run and completed, ready for the next job.


Colour communication or modern day


proofing devices, such as the FlexiProof and variants for users and producers of flexo inks, and the K Printing Proofer for proofing flexo ink, gravure and gravure-offset, have been developed by RK Print Coat Instruments. Another system that minimises process problems, speeds product development and which can be used to trial materials, formulas and undertake small scale production is the Rotary Koater, a pilot coating, printing and laminating system. The Rotary Koater enables users to select


from almost two dozen print head and coating technologies; wet or dry lamination can be undertaken and a variety of drying technologies, including hot air, infrared and UV curing, are available. The Rotary Koater is particularly suited for laboratories, research centres and converters faced with frequently changing product requirements, where different coating and other technologies may need to be assessed. For clients with known print/coat or laminating requirements, companies or organisations that require a bespoke built-to- order machine, the VCM may be the answer. The VCM is built to high specifications and is designed for seamless integration into product development, trialling, workflow and investigative workflows. www.rkprint.com


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