Film & Foil
Clarity and vision in flexibles By Tom Kerchiss, chairman of RK Print Coat Instruments
P
roduct visibility can be advantageous. Clear packaging in some circumstances minimises the use of labelling and reduces on-pack printing. Clear packaging, used in conjunction with vision inspection and capture/ divert technology enables processors using fl ow line conveyor systems to more readily detect errors prior to shipment.
Some brand owners of food and beverage items have had moments of clarity and vision. Morning goods such as breakfast cereals; yogurts; fast foods items; chilled foods, the sliced ham, the smoked salmon and deli items appear in clear packs or with reveal panels enabling the shopper to see inside before they buy. Food revealed gets a cautious welcome from many consumers; marketers and brand owners however, have to exercise some caution. With most fl exible packaging applications, the business of putting in protective barriers is of concern.
Food manufacturers must adjust recipes, as some foods can look very unappealing. Print and packaging success depends to some extent on the resourcefulness and skill of the converter and in material selection and in the accuracy of processes such as die cutting, coating and the application of adhesives.
Food items displayed must be contained while presentation is optimised. Packaging fi lm that becomes misted up when kept in the chiller cabinet, or those food contents, particularly meats in the reveal that look grey due to poor seal or welds, hampers sales and can aff ect the brand. Converters must take into account the characteristics of the substrate, the tear resistance, extensibility, seal and (if relevant) peel strength,
the end user requirement; security, aesthetics and printability. The gradual move away from multi-web structures to mono-materials for reasons of effi ciency, recyclability, sustainability and the environment is not insignifi cant and requires partnering up and often of experimentation. Advancement in polymer science is enabling converters and technologists to address challenges associated with mono materials and biodegradable fi lms and with processes such as coating and food compliance requirements such as protective barriers.
Packaging protective requirements vary greatly: some applications require a barrier against oxygen and water vapour, some demand chemical resistance and protection from ultra violet light; still others need microbial barrier. Sometimes providing a barrier is not about preventing something getting in, it is about preventing something inside from getting out, an example being aroma. SUP incorporating metallised foils are at this point in time still the best option for maintaining the freshness and aroma of coff ee. Selection of materials when designing a package depends on many factors. If a clear barrier resistance is needed, there are many clear material options available to select from, including those which it is claimed compare favourably in terms of barrier resistance to thin gauge aluminium foils. In perfect condition, without pinholes or process imperfections foil is theoretically impervious to moisture, light and gases. In reality though thin gauge foil of around 25 microns or less, will be subject to pinholes. This and of course the lack of transparency precludes foil for many applications. Formable barrier materials that off er excellent clarity
12 September 2025
include ethylene-vinyl-alcohol (EVOH) as a co-extrusion. EVOH as well as nylon are viewed in some quarters as having a neutral eff ect on recycling streams when combined with PE or polyethylene. PE is in itself either LDPE, LLDPE or as HDPE count as mono material with an additional added recycled content.
It goes almost without saying: product developers, packaging technologists, converters and others with input (ink, coating, adhesive suppliers) must have the most suitable processing, monitoring and product development devices in place. Products must be trialled to ensure products are compliant. Barrier coating of mono material; a move by many towards using water based inks and coatings and a need to conform with ISO, Six Sigma and other regulatory requirements has meant that pilot/production coating/converting machines are often purpose built or bespoke systems.
RK Print Coat Instruments VCML pilot print/coating system with a working web width of up to 300mm enables users to print, coat and laminate on all types of fl exible substrates and on a reel-to-reel basis. The VCML can be used for small-scale production so that products, processes and diff erent methods of coating, printing, laminating or drying/infrared and UV curing can be assessed.
An alternative, the customer bespoke VCM pilot/ production machine incorporates high specifi cation drives, tension and web control equipment with rigid framework surround, which facilitates the processing of wider and heavier substrates. VCM design allows for considerable fl exibility enabling the system to be expanded or modifi ed over time when processing or product development needs change.
www.convertermag.com
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