Contracting labeling is becoming more and more popular, and it is growing rapidly at a rate of two digits per year. The reason why such results have been obtained is at least due to two reasons. First, shrink labels can make full use of the surface of the entire container and play a very good role in the reproduction and transmission of images and information. On the other hand, the container itself can also be made into a variety of unique shapes that are not subject to subsequent labeling restrictions, which can greatly enhance the shelf appeal of the packaged product. However, due to these special shapes, higher requirements and challenges are placed on the label materials and their printing inks. In addition to dealing with the problem of adhesiveness of non-porous film materials, shrink label printing inks also have to deal with several other factors in order to achieve better development, including deformation (scratches, delamination, etc.), paste, and low COF (Friction Coefficient) and low odor for food and beverage packaging. These requirements also promote the further development of printed materials and inks. Suitable for specific materials In terms of materials, PVC, PETG, and OPS account for most of the market for shrink labels. According to Manuet Rivas, technical director of the PPL division of Siegerwerk, the former two occupy 90% to 95% of the market. Because each film has its own surface characteristics, Rivas emphasizes that each film requires the use of a specific ink composition for proper performance. To meet changing needs, S iegwerk offers solvent-based inks designed specifically for each type of shrink-thinning material and printing process. In addition, flexographic printers using water-based inks can print on their corona-treated PVC and PETG films using their CWS-2100 series inks, while the SICURA series inks can meet the requirements of UV printing. In order to facilitate the selection of inks, the company also introduced solvent-based ink Access Sleeve, which is suitable for all film materials. INX International Ink Corporation has developed the S hrink P ac series of inks that can be used in a wide range of materials for a variety of printing processes, such as the ShrinkPac for gravure printing and Flexo ShrinkPac for flexographic printing. “At the same time as simplifying and speeding up the turnover of our jobs, our inks also solve many of the other problems that shrink label printers routinely encounter,†said Luigi DeFlaviis Jr., head of INX's liquid ink division. Towards multi-purpose development While ink suppliers offer a range of ink products to meet a particular shrink label print, inks that are suitable for a variety of shrink label materials are gaining momentum. “In the past, many inks were suitable for a specific material, and now, the newer series of inks exhibit multi-functional properties on a variety of materials,†said John Kalkowski, North American Marketing Manager at Sun Chemicals. It will help reduce the number of press cleanings, reduce cross-contamination, and help control the amount of ink used." One of the latest developments from XSYS is Flexocure XSUV radical-curable ink, which provides 70% shrinkage and is suitable for a wide range of film materials, including PVC, OPS, OPP, PET, and PETG. It can also be used for surface printing and India. And Fujifilm's Uvisleeve is another UV flexographic printing ink designed according to various characteristics of the shrinking process. The company's marketing manager, Fultz, emphasized Uvisleeve's several key qualities, such as low COF, low chemical odor, and maximum shrinkage to facilitate shrinkage of the label material. In addition, they also provide high opacity white ink. The effect of low COF is mainly reflected in the process of seaming, which allows the sleeve to quickly pass through the labeling device after sealing. When designing UV inks for shrink label printing, Bob Waddington, general manager of UV itec, pointed out that the selected resins and photoinitiators must take into account the shrinkage of the film, do not scratch the material, and at the same time have relatively good in a relatively cold environment The performance will not be distorted. UVitec recently introduced a new line of UV shrink label printing inks with improved scratch resistance and delamination resistance. Water Ink Technologies offers both water-based inks and UV inks, all of which can be applied to conventional shrink label printing. Processors can use the best characteristics of each ink to meet their respective needs, such as the economics of water-based inks, the opacity of UV inks, or the efficiency of nesting.
Reprinted from: Printed Materials in China