Shrink Label Savvy

Shrink sleeve label printing requires a lot of work, but the rewards can make it all worth while.

SHRINK SLEEVE LABELING has taken aim at the product decoration market in a big way. It's not doing this with a single-shot sniper's rifle, either. It's blasting away at market opportunities and market share with both barrels. Shrink labels represent a high-growth segment in product decoration, and those package printers with the technical savvy to make it work are reaping the benefits of its market appeal.

Technical savvy is the key, because a shrink label is a moving target—it starts out in one shape and ends up in another. Graphic design, label production, and label application all have to be done with the utmost care and skill.

packagePRINTING contacted a number of package printers that are veterans in the shrink label business—Fort Dearborn, Logotech/Tadbik, Multi-Color Corp., and SleeveCo. They provided a rundown of this exciting segment of the product decoration market in terms of market and process considerations.

Market play

Shrink sleeve labels are making their presence known in many consumer markets, but the beverage market is clearly leading the way. "By volume, the largest product category using shrink sleeves is the beverage market," says Martin Wilson, director of sales and marketing for SleeveCo. "Even when dividing this market into subcategories you find that by volume, they outpace many other markets. Examples include dairy, juices and teas, and nutritional drinks."

Other markets promising solid growth include food and health and beauty aids (HBA). "The demand for portability and single-serve meal and snack options is fostering continued growth within the food market as well," says Shannon Kroner, marketing business analyst for Fort Dearborn Company. "Many of the current products that cater to these trends are packaged in plastic containers decorated with shrink labels."

The benefits and functionality offered by shrink sleeves fit well in HBA, says Wilson. "They are a perfect match for the product differentiation and branding necessary in the HBA markets."

According to Micha Noah, R&D engineer for Logotech/Tadbik, shrink sleeves can also be used to unite more than one product into multi-packs. With shrink sleeves, individual packages can be securely combined, while highlighting the shapes of the packages.

This appears to be a further opportunity beyond individual package shrink labels. "Warehouse and club stores of the world continue to take in a significant percent of the consumers' dollars," says Kroner, "especially as they reduce the amount of oversized bulk items and switch to regular-sized items in multi-packs. This trend, too, will create growth for shrink sleeve applications, as many multi-packs are bundled and decorated using shrink sleeves."

Printing processes

For these shrink sleeve printers, there's no one printing process that meets all their needs. Flexographic, rotogravure, offset, and digital are all being used in one form or another to meet the specific needs of their individual customers.

SleeveCo uses rotogravure presses from Chesnut Engineering for continuous print, infinite repeats, and high line screen printing. PCMC flexo presses are used in specific customer applications. Multi-Color also runs both gravure and flexo, with gravure doing the lion's share of its shrink label work.

Logotech/Tadbik runs its shrink label products on offset machines, including a new GOBEL NOVAPRINT 680MM press. According to Noah, the main reason for choosing offset over gravure was the cost factor—the low cost for offset plates in comparison to gravure cylinders. "As for quality, we receive an almost identical product when we compare offset to gravure—and a far superior product compared to flexo print. For opaque white or metallic inks or other special inks, we have two gravure units on our GOBEL, positioned as first and last stations on the machine."

Fort Dearborn runs three different printing processes—flexographic, rotogravure, and digital—and can print up to 9 or 10 colors in both narrow- and wide-web formats. "Offering this range of print technologies allows [us] to provide a suite of printing solutions to customers, each technology meeting a different packaging need," says Kroner.

Flexo is used for high-quality, medium-size runs, while rotogravure is used for longer runs and for applications that require a higher degree of opacity. Fort Dearborn's HP Indigo ws4000 digital press is used for small runs, variable graphics, samples, and label prototypes. These capabilities "compliment the new package development process and provide low volume cost efficiencies across the label supply chain," reports Kroner.

Material considerations:

Substrates and inks

The primary substrates used for shrink labels include PVC and PET/PET-G, with some OPS in use. SleeveCo also reports using some PLA (polylactic acid), a compostable film made from a corn base resin.

The selection of the substrate requires matching the shrink properties of the film with the shrink requirements of the specific application. This sounds pretty simple, but it involves many factors. "Aside from cost," says Kroner, "shrinkage requirements, shrink line layout/equipment, container design, container material, line speed expectations, and environmental issues also impact substrate selection."

Noah advises clients on substrate selection in many areas around the world, including Israel, Europe, South Africa, and the United States. The needs of the different geographical areas have a big impact on material selection.

Because recycling is strongly emphasized in Europe, Noah says that PET represents the majority of its market. "If a company wants to emphasize recycling, we suggest PET," he reports. "Otherwise, because PVC is significantly less expensive than PET, it is a much more common choice in the States, South Africa, Russia, and Israel."

Shrink sleeve material includes many different grades, from high-shrinkage to fast-shrinkage. Which grade to choose and even its thickness depends on the shape and material of the container, along with the sleeving equipment and the line speed, says Noah.

"For lines running at speeds of around 100 pieces per minute, we can go with a thinner sleeve. For lines that run at 150 pieces per minute, we select thicker material (50 to 60 microns). We also look at the shrink tunnel—whether it is air or steam, ceramic or fan. These factors can affect the amount and speed of shrink. A poor tunnel can result in poor performance of the film, so we have to consider that when we choose our material."

The types of inks used by these printers run the gamut from water- and solvent-based, to UV and digital inks. However, no matter what ink technology is employed, the specific ink formulation used with shrink labels must be able to withstand the high temperatures from the shrink process, says Multi-Color's Marketing Program Manager Angela Santos.

Kroner lists several additional considerations, including the nature of the product in the container, the amount of shrink, and opacity. Because some inks can migrate through the containers and potentially contaminate the product, certain inks cannot be used for food or beverage products.

Opacity can be a significant consideration, depending on the color of the container being used, or the color of a product packaged in a clear container. "Dark containers and/or dark product will cause certain inks to look dull or darker than intended," she says.

To address potential ink migration problems and product contamination, Logotech/Tadbik uses UV-based inks that are FDA-approved for indirect contact with food. Noah also reports recent success with the use of metallic, pearl, and lacquer matte and iodine inks that change color as the viewing angle of the package is changed.

Logotech/Tadbik has also been an early adopter of the use of dry glue in shrink label applications. "We apply special, heat-activated glues as if they were a color on the press. We choose the glue based on the package—we have glues for PE, PP, and glass. The glue allows us to avoid label slip, and it is nearly invisible."

SleeveCo customizes its solvent-base inks in-house. "We get our pigment bases from Sun Chemical and have a proprietary, in-house ink dispensing and blending system that custom manufactures and formulates our own inks for flexo, gravure, fade-resistant, and lamination inks," reports Wilson.

Not for the faint of heart:

Design through production

Getting the graphics to appear just right on the final package after the film shrinks some percentage in both the x and y directions is the obvious challenges presented by shrink labels. And the graphics have to look just as good, if not better, than graphics printed on a more stable substrate, such as pressure-sensitive paper labels.

"One of the most common concerns initially in the printing of these labels is the graphic distortion that will occur as the label shrinks to the container," says Santos. "This must be taken into consideration when designing the graphics." It requires a firm understanding of the shrink curves of the different materials, and is important in both the printing and the application of the labels.

"Predicting the distortion of the graphics remains one of the most difficult hurdles when preparing the sleeve for production," says Noah. However, there are some tools that have been developed to help meet this challenge.

Logotech/Tadbik uses Artwork Systems' ArtPro graphic software in this effort. Using this tool, Noah can get a virtual view of the finished sleeve on its container, with the required distortion automatically determined.

Once the design is established, the challenge becomes one of making it work thousands and thousands of times each day on the production floor. This is no simple task, and the consistent performance of the inks and substrates plays a key part.

"There is a learning curve as with any market," says Wilson. "However, the learning curve in the shrink market is much greater than say the tag and label, roll-fed, or pouch market. Understanding your incoming raw materials and how they will perform under the application and shrinking conditions are critical."

According to Kroner, the learning curve was also a significant issue for press operators who were accustomed to more stable substrates. In addition, "Significant modifications had to be made to the printing equipment to allow economic production of the sleeve materials. Considerable investment in finishing equipment was required, as well (seaming and inspection)."

What this all boils down to says Kroner, is that the "converter must be involved much earlier in a package development project versus any other labeling project because of the vast number of interdependencies encountered with a sleeve throughout the supply chain."

The digital printing capability in Fort Dearborn's arsenal provides a big lift in the overall effort. "Digital printing is ideal for prototyping shrink sleeves for contoured package shapes in order to understand the distortion of graphic elements and the color space for the printing process," says Kroner.

Business opportunities

There is a clear consensus among these printers that the ability to supply shrink sleeve labels has made a significant positive impact on their businesses. Says Santos: "Adding shrink sleeves to Multi-Color's portfolio of offerings has certainly broadened the value proposition that we offer our customers. It opens the door for new business and additional business growth within current customers. The addition of this technology also provides current customers the opportunity to grow their business while maintaining just one vendor."

Wilson has a similar message as to the impact of shrink sleeves on SleeveCo's success. "SleeveCo's primary growth driver has been the shrink sleeve market. This new business has come from existing customers introducing new products and rebranding old products, and also includes a great deal of business from new customers."

By Tom Polischuk

Editor-in-Chief