Around 50 percent of all self adhesive label usage is in the broad area of transport and logistics labeling, according to FINAT, the European association for the self adhesive label industry. This dramatic statistic underlines the fact that, across all the end-use market segments – including food, drinks, pharmaceuticals and retailing – self adhesive labels have established an unmatched reputation for reliability, coupled with versatility, in every respect. They are a preferred choice because of the extremely stable nature of the self-adhesive “sandwich” – a laminate of printable facestock, adhesive, and the release liner that carries it along the press. The advanced reel-fed label presses used for self adhesive label print are ideal partners: they combine high-quality print options (many different print processes); label diecutting and finishing (varnishing, etc); waste stripping, and rewinding into reels ready for application.
The physical demands
In transport and logistics applications, the demands on the physical qualities of a label are stringent: these are functional labels that must perform in a variety of environments to meet users’ needs. After all, the actual substrate to which they will be applied may vary from wood to rough card, plastic (films or containers), glass, and even such specific items as tires. Self adhesive labels offer a choice of adhesives delivering reliable adhesion to a variety of different substrates, or – for critical applications -- substrate-specific adhesives.
But that is only part of the story. The label’s facestock – its printable surface – must be able to conform to the pack to which it is applied. On flat surfaces, this is no challenge – but the situation is very different when it comes to curved packaging or “difficult” surfaces such as apolar plastics which repel standard adhesives. Storage conditions – wet and damp, in particular – will also affect facestock choice.
Additionally, although visual aesthetics are not normally associated with transport and logistics labeling, clear readability is essential (either by the naked eye or with scanners). The imaging methods used for such labels also, therefore, make demands on the choice of label facestock. With self adhesive labels, the ability to choose a preferred or special-purpose facestock and combine it with a preferred adhesive, and a release liner ideally suited to the label application method employed is a considerable benefit.
Applying the label
The actual application of a logistics label to a pack may be accomplished, according to the application concerned, manually, with a hand-operated labeler; or automatically via special self adhesive dispensing equipment. For highly-sensitive products such as ethical pharmaceuticals, specially constructed secure tracking systems can create a track-and-trace continuum through the entire supply and distribution chain, from manufacturer through distributor and transport company, to the dispensing pharmacy.
A variety of roles
Setting aside the physical requirements, logistics labels also undertake a variety of important roles. They identify single items at the retail point of sale, in catchweight applications, particularly for foods. Here, the label’s dual readability role – correctly identifying the contents for the consumer and enabling the sales assistant to successfully scan the item at the checkout – is critical. In warehousing and other inventory situations – at single item or pallet level – labels are key players in stock control. They can also perform a major function in product authentication and tamper evidence – often at the leading edge of today’s security labeling technology. Using a self adhesive label as a carrier of security solutions can be a cost effective solution for brand owners, and converters active in the self adhesive label production market are contributing extensively in this market.
Self-adhesive labels, whether pre-printed or not, can employ all the types of variable information print (VIP) required to perform these different functions. They will often combine alphanumeric (product name or code) identifiers, for reading with the human eye, with digital identifiers such as bar codes, for use with special readers employed in the track-and trace technologies. Automated stock control makes tough demands on labels; and as well as dependable adhesive technology, the labels must feature a face material – usually paper but, today, also film – that delivers high quality print by a variety of VIP technologies.
The bar code
Bar codes as product identifiers are today’s most ubiquitous track-and-trace technology. They have been around for nearly half a century, but they still play a key role in supply chain management in many different ways, securing and documenting a variety of information from unique product identifier to production location, batch number, and expiration date. The simple one-dimensional bar code has been joined today by two-dimensional barcodes and, based on the 2D technology, even three-dimensional bar codes. Self adhesive labels can accommodate even the most advanced bar code technologies – even those associated with today’s product authentication technologies.
Variable information print technologies
In all its transport and logistics applications, a bar code is often applied to a product via a simple label, sometimes pre-printed with a logo or other message, often in partnership with other variable information print. The image today can be created by direct thermal, thermal transfer, inkjet (including flatbed) and laser print processes. Bar codes may also be applied as unique identifiers on primary product labels via digital print units in modular narrow-web press configurations, or via the standalone reel-to-reel digital label presses.
The mature direct thermal technology, which creates images using heat on a heat-sensitive substrate, primarily serves the retail market, particularly for catchweight food labeling. It offers ease and reliability of use for short-life applications, and delivers relatively low-cost quality barcodes at reasonable print speeds. These characteristics also make direct thermal an obvious choice for transit product identification and tracking labels, e.g. for parcel distribution, as well as for outer case and pallet markings.
It is worth noting that traditionally self-adhesive Bisphenol-A (BPA) has been used in thermal papers as the standard image developer – but current concerns around its possible toxicity have led the manufacturers of self-adhesive thermal labelstocks to offer non-BPA alternatives.
Thermal transfer, using ink ribbons with a thermal printhead, is one of the most flexible variable information print technologies, due to the variety of ribbons and printable receiver label materials (many UL approved) available, and its ability to print in color. Image quality and durability can be very high, so thermal transfer has been an ideal choice for industrial label applications such as chemical drum labels and durable component markings for electronic, automotive, or white goods.
Bar code reading
From what was originally a "professionals only" operation, bar code reading has also become an option for the world’s camera cell phone owners, for whom another "app" is available: the ability to use their phone to read a 2D barcode via a QR (Quick Response) code on a label, and connect via WiFi to retrieve product information and traceability. This technology is now finding favor as an alternative to "specialist" readers across the professional logistics and track-and-trace market, and adds another dimension to the available options with self adhesive labels.
International standards for the many available bar code system platforms are now resident within the global GS1 supply chain management standards association. They include EAN/UPC, ITF-14, and GS1 DataBar and DataMatrix, as well as the EPC global standards for RFID implementation.
While standard bar codes require line-of-sight "reading," RFID (radio frequency identification) does not. Indeed, as prices for RFID tags have come down, the technology has been adopted in many key application areas – particularly in the retail environment, for item-level stock management as well as security. RFID has proved a highly-flexible technology, regularly partnered with self-adhesive labels, and it continues to develop new functionalities. RFID "smart labels" – consisting of a chip and antenna – are usually applied to a pack or product contained within the self-adhesive label laminate, which offers the option of additional print on the label face. Both passive (generally read-only), or active tags (tag data can be modified or rewritten, and can be transmitted over a longer distance), can be accommodated in self-adhesive labels, for reading either with a handheld device or via a computer portal. Tags may be overt – visible on the package – or covert, according to requirements.
The number of levels at which authentication, tamper-evident, and track-and-trace elements can be added to products has grown exponentially. The devices may be overt or covert, to provide the broadest possible umbrella of protection for everything from ethical pharmaceuticals, foods and beverages, and medical devices to legal documents, designer handbags, automotive and aerospace parts, toys, CDs, and consumer electronic goods.
Security and track-and-trace solutions are often layered on item-level packaging in customer-unique (and even product-unique) applications, especially for high-value goods. They will combine overt and covert options. Many of these options are incorporated in the stock-in-trade of the self-adhesive label converting companies who provide pre-printed logistics labels or rolls of label "blanks," to meet product manufacturers’ increasing needs for authentication. Security features such as customer-exclusive watermarks, UV- or IR-light-detectable fibers and chemical taggants can be engineered into a self-adhesive label substrate. The label converter can also add visible and invisible features, on press, at a number of levels, using, for example, "sympathetic" inks (reactive to changes in light or temperature) and varnishes, or special diecuts to create product-unique identifiers.
All in all, the self-adhesive label offers unmatched flexibility and versatility in both straightforward day-to-day inventory labeling, and in advanced options. Self adhesive label converters around Europe, and their labelstock suppliers, are both an excellent source of information on the extensive opportunities available to brand owners and other companies transporting goods across increasingly wide geographies. Whether transport and logistics label volumes are large or small, simple or complex, and whichever imaging processes they utilize, it is worth talking to a self-adhesive label converter to learn how any specific track-and-trace labeling challenge can, successfully and cost-effectively, be met today.