Film and Foil
The brilliance of foil and metallised film
By Tom Kerchiss – chairman of RK Print Coat Instruments Ltd F
ew materials are subject to so many prejudices and misunderstandings than aluminium foil. In its raw material state, bauxite is exceptional in that it is one of the most common minerals on the planet. Never the less, aluminium or rather the manufacture of aluminium is subject to considerable controversy. Environmentalists often give foil the thumbs down as the conversion of even a single tonne of aluminium through melt-electrolysis may involve the use of upwards of 17, 500 W/h of electrical energy. Foil advocates counter by saying that this is more than offset by the fact that, for most applications, foil is both lightweight, milled thin and slit down to more manageable sizes; a case of a little going a long way. It is also combustible and as a household waste contributes to the possibilities to recover thermal energy from an incineration process. Foil is frequently used as part of a laminate and is produced in widths of 2 metres and then rolled out to thicknesses of as little as 6.65 microns. Theoretically, the barrier
properties of foil are better than other flexible packaging materials. The sheerest of foil when used in conjunction with film makes the film impervious to liquids, gases and light. Care needs to be exercised when printing and converting foil, metallised papers and film. The brilliance of the surface magnifies surface blemishes and any inconsistences of colour. Foil, especially when being used for barrier purposes requires care when handling and when adding value. As foil tends to be ultra thin, it may on occasion be subject to microscopic nicks as it travels at high speed through the laminator.
When marketers and brand owners want to create a shimmering or reflective look and when barrier resistance is less of a concern, then metallised film and papers may be chosen. The process of metallisation is undertaken by air-to-air systems or via roll-to-roll systems. The process involves coating a plastic film with a thin layer of metal of around 10 to 18 microns under vacuum conditions onto a
continuously moving web at high speed. Normally
metallisation is not the final process, subsequent value added processes such as printing, cross cutting, varnishing, lamination are undertaken.
The radiance of foil, metallised films, papers and specialised inks has long been appreciated for their ability to convey prestige and quality. In quality focussed markets, printers and converters must weigh up the advantages and disadvantages of the various materials they use and whether the inks they intend to print with, coat with, laminate with are the most suitable for the application and for the audience that
the product is being directed towards. Pearlescent inks differentiate one brand from another when the product is seen on shelf in the retail environment. Hot stamping of foils or holographic materials are ideal for the decoration of cosmetic secondary packaging and for many other sectors that want to maximise retail stand out. For specialists operating in security and
anti-counterfeiting reflectivity, detectability and preventability may best be served by optical variable devices (OVDs) or even diffractive variable image devices or DOVIDs. Consistency of quality is of paramount importance. The metallic, pearlescent, gold, silver and other reflective inks need constant monitoring. Excessive mixing and agitation can degrade the light scattering effect. Variables such as colour deviation, blemishes, colour casts and pinholes impact on quality and product viability. Colour communication devices are used to address flexographic print process concerns.
RK Print Coat Instruments have supplied a number of VCML pilot coating, print and laminating systems for holographic material production. With a working web width of 300mm, the system enables operators to print, coat and laminate on all types of flexible substrates. Users have access to a wide range of applicator technologies such as slot die, knife-over-roll, flexo, gravure, direct gravure, reverse and offset gravure, screen and more that ensure the most economical and practical technology can be selected. Drying options include hot air, infrared and UV curing. Zones can be ATEX explosion proof protected and it can be configured for clean room conditions.
14
September 2024
www.convertermag.com
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58
