Inks That Shrink

With the use of shrink-sleeve labeling for product decoration growing at a double-digit rate, suppliers of shrink film inks are developing a steady stream of products to carve out a piece of the action. But in addition to the normal adhesion issues that are common with non-porous film applications, shrink inks have several other factors to contend with that make their development more challenging. Some of these issues include distortion (cracking, delamination, etc.), blocking, coefficient of friction (COF), and in food and beverage applications, low odor.

Demanding applications

Shrink labeling is growing in popularity because it offers brand managers at least two advantages. It provides full use of the container for graphics and messages, and the container itself can be formed into unique shapes that enhance shelf appeal. These shapes, however, add to the technical demands on the inks and substrates.

For substrates, PVC, PETG, and OPS make up the majority of shrink films, with PVC and PETG accounting for 90 to 95 percent of the market, says Manuel Rivas, director of technology, PPL Division of Siegwerk. Because each of these films exhibits different surface properties, Rivas notes that traditionally, “each of these films requires the use of specific ink chemistry for appropriate performance.”

To meet the varying requirements, Siegwerk provides solvent inks that are specifically designed for each of the film substrates and printing processes. In addition, flexo printers using water-based inks can use its CWS-2100 series inks on corona-treated PVC and PETG films, and the SICURA line is available for UV applications. Also, in an effort to simplify ink inventory concerns, the company offers a solvent-based ink system, called Access Sleeve, that works on all films.

INX International Ink has developed its ShrinkPac line for use with multiple substrates using either gravure (ShrinkPac) or flexo (Flexo ShrinkPac) printing processes. “While this simplifies and expedites job-to-job turnaround, our ink formulations also solve problems encountered daily by many shrink-label printers,” says Luigi DeFlaviis Jr., director of national accounts for the Liquid Ink Division of INX.

Although ink suppliers can offer an array of products that are designed for each particular substrate, there is a definite trend towards ink systems that can handle multiple shrink-film substrates. “Traditionally, many inks have been substrate specific, but newer ink series offer more versatility on a variety of films,” reports John Kalkowski, North American marketing manager for Sun Chemical. “This helps reduce press wash-ups, cross contamination, and helps to control ink usage.”

One of the latest developments from XSYS Print Solutions is Flexocure XS, a UV free-radical technology which is designed to provide more than 70 percent shrinkage. It can be used with a wide range of films including PVC, OPS, OPP, PET, and PETG, and can also be used for both reverse-side and front-side printing.

Uvisleeve from Fujifilm Sericol is another UV flexo ink that is designed to address issues brought about by the shrink process. Jon Fultz, marketing manager, packaging, highlights several of Uvisleeve’s key attributes as very low COF, low odor chemistry, maximum shrinkage so as not to interfere with film shrinkage, and the availability of a high-opacity white ink. The requirement for low COF comes into play in the seaming operation. It allows the sleeves to be seamed and run across sleeve applicators at high speeds.

In formulating UV inks for shrink applications, Bob Waddington, general manager for UVitec, points out that the resins and photoinitiators must be selected to “allow for the shrink of the film and not crack off the substrate, as well as function in a relatively ‘cooler’ environment [no distortion].” UVitec has recently introduced a new UV shrink sleeve ink system that has improved resistance to cracking and delamination.

Water Ink Technologies provides both water-based and UV ink systems that can be used with all the commonly used shrink films. Converters can use the best features of either system to meet the needs of their individual applications—the economy of water-based systems or the opacity and sleeving efficiency of UV inks. n

Shrink label innovation

Gilbreth, a Croydon Pa.-based label printer, has recently marketed some unique shrink label products for the consumer products market. Gilbreth Rub ‘N Smell printed sleeve labels provide a multi-sensory shelf package experience that delivers a distinctive visual presentation and aromatic preview. Without opening the package or compromising the product, an interactive, sensory bond can be formed between the consumer and the product. Rub ‘N Smell shrink labels incorporate tiny embedded fragrance beads that are activated by a gentle rubbing motion. The aroma can be reactivated with successive rubbings, which do not have a detrimental effect on the printed graphics.

Gilbreth also introduced an iridescent shrink label (left) that can provide enhanced shelf appeal for wine, spirits, upscale beverages, and beauty and fragrance packs. The iridescent shrink labels display a continually changing rainbow of color. As the film interacts with light, it projects a kaleidoscopic pattern of color that provides eye-catching appeal.

Resources

Alden & Ott www.aldenottink.com

Environmental Inks and Coatings www.envinks.com

Fujifilm Sericol www.fujifilmsericol.com

INX International www.inxinternational.com

Rad-Cure www.radcure.com

Siegwerk Ink Packaging www.siegwerk.com

Sun Chemical www.sunchemical.com

Water Ink Technologies www.waterinktech.com

UVitec www.uvitec.com

Wikoff www.wikoff.com

XSYS Print Solutions www.xsys-printsolutions.com