Pressure-sensitive labels provide critical information-from safety instructions on mechanical equipment to dosage requirements on medications. Yet creating the right labels for durable goods is no easy feat.
It’s important that labels convey essential information, maintain the brand’s aesthetics and perform to exacting standards. But that’s not where label performance ends-manufacturers must deal with a host of additional requirements based on the type of product for which the label is being created.
Multiple ChallengesThe label material, or substrate, must achieve key performance factors and functionality, such as adhering and remaining legible throughout temperature extremes, exposure to volatile chemicals, and exposure to UV light. In addition, due to the complexity of today’s retail supply chains, inventory management requirements, asset tracking and birth-to-death product tracking requirements, many labels are now printed with bar codes that must remain legible throughout the product lifecycle.
Unfortunately, no single substrate will work for all applications. The performance of the label is impacted by numerous factors, including the surface to which it is meant to adhere. For example, a surface with high surface energy (easy to adhere to) may require a different adhesive than a material with low surface energy (e.g., new low-cost in-mold plastics) in order to adhere properly.
Even seemingly small changes in the application surface can alter the adhesive choice. For example, while labels on snow blowers and lawn mowers have similar requirements for brand identity, warning requirements, and compliance issues, they are also very different. Snow blowers are exposed to sub-zero temperatures, which require adhesives that can perform under those conditions. Alternatively, lawn mowers are exposed to high temperatures and considerable abrasion. Thus, a label that performs well on a snow blower is likely to fail on a lawn mower, and vice versa.
In addition, many of today’s applications require specific testing to comply with various agency compliance standards, such as UL, American Gas Association, military, automotive and Nuclear Regulatory Commission guidelines. However, the process of testing labels is costly and time-consuming. Several new approaches are emerging to help tackle these complex label selection and validation challenges.
Consultative ApproachWith so many factors involved, it can be difficult to predict label performance. After all, no single adhesive sticks to all application surfaces, no single topcoat is compatible with all print technologies, and no single liner works well for all printing or converting methods. Determining the best label construction involves a consultative approach to substrate selection, taking into consideration the application requirements, application surface, print method and more. During this process, it’s important to ask key questions, such as:
- Will the product be used indoors or outdoors?
- What is the application surface (material, cleanliness and smoothness)?
- What will the label be exposed to?
- Where on the part will the label be applied?
- What is the expected product life?
- How will the label be applied?
- Will the label be printed and/or converted in sheet or roll form?
- Will there be an overlaminate or overprint varnish?
Prequalifying Ink and Substrate CombinationsDurable goods manufacturers usually don’t have the time, money or inclination to certify inks and substrates for UL certification. To alleviate this challenge, UL and substrate and press manufacturers are collaborating to make the approval processes less complicated. Through this up-front process, several combinations of substrates, presses, and inks have already been UL approved, allowing printers to simply adopt these substrates and inks to produce UL-compliant labels.
For example, certain FLEXcon substrates and Jetrion inks are prequalified and approved by UL for converters that need to produce a PGJI2-certified label. Manufacturers can choose from these recognized substrates and inks with the confidence that the resulting high-performance labels will meet key aesthetic and durability characteristics without an up-front investment.
Analytical TestingManufacturers are also taking advantage of new testing methods that accurately predict substrate performance under a variety of environmental conditions. Temperature- and humidity-controlled ovens test the substrate’s ability to withstand considerable heat. Similarly, abrasion testing validates the product’s durability against scuffing and scratching.
Cryogenic testing is ideal for testing substrate performance on products such as polymer test tubes that need to perform in freezing conditions. The system tests substrates down to -80°C, validating that bar code labels identifying blood or DNA samples are durable at extremely low temperatures.
Xenon Arc Weather-Ometer® testing* exposes substrates to light, heat and humidity. Real-time weather testing is performed in a way that mimics years of outdoor weather exposure. Adhesion testing encompasses multiple test methods that evaluate peel strength, seal strength, adhesion strength, and mechanical properties of adhesives and adhesive systems. Most importantly, end user testing includes fit-for-use-testing to ensure that the substrate fully satisfies performance, aesthetic and functionality requirements.
Real-World ExampleThese approaches help durable goods manufacturers make the right substrate choice, validate that the substrate will perform as needed, and help save time and money in the process. For example, a global manufacturer of outdoor power equipment recently lowered its total applied costs for nameplate applications by using FLEXcon PSA films. Previously, the company had used a polycarbonate material based on its durability. However, the polycarbonate was costly, and the manufacturing process required to produce the sheeted nameplates was time consuming and labor intensive.
The production of the polycarbonate nameplate material required a three-step process. In addition, the product had durability issues. While polycarbonate resists impact and abrasion, it discolors in the face of prolonged exposure to UV sunlight, causing the manufacturer’s nameplate to degrade over time. The company needed a solution that would improve application efficiency, extend outdoor label performance, and lower total costs without sacrificing aesthetics.
To resolve these issues, FLEXcon presented the company with a pressure-sensitive label solution. FLEXcon identified an ideal set of materials, with graphics printed on FLEXmark vinyl base film and protected from weathering and abrasion by DPM® CVE clear polyolefin overlaminate. The result was a textured surface similar to the more costly polycarbonate.
In addition, the self-adhesive label stock eliminated the need to apply a transfer tape and could be printed flexographically in roll form, replacing the three-step operation with a single-pass process. The durability and scratch resistance of the new product construction is as good as or better than the old polycarbonate product. Less expensive materials-paired with in-line, roll-to-roll flexographic printing and overlaminating-made the new nameplate labels less expensive to produce.
Careful Selection Pays OffWith a myriad of factors influencing substrate performance, manufacturers can’t leave anything to chance. Taking a consultative approach to substrate selection and validating this selection through performance testing prevents costly mistakes. Moreover, choosing a pre-certified substrate and ink saves manufacturers money and speeds time-to-market by eliminating the UL approval process.
For more information, contact FLEXcon at 1 FLEXcon Industrial Park, Spencer, MA 01562; phone (508) 885-8440; fax (508) 885-8355; or visit www.flexcon.com.