From:Packaging World

Labels arrest attention and influence consumers’ buying decisions while communicating brand, product-line, instructions, and other pertinent information. In addition to those traditional functions, labels are increasingly part of tracking and anti-counterfeiting strategies. Pressure-sensitive (p-s) labels—as with other types— typically will be the least expensive packaging component (compared to the container and closure, for example); nonetheless, cost-effectiveness, in addition to suitability, is application-specific.

P-s labels have a top coating (i.e. lacquer or varnish) to protect surface printing and have an adhesive on the bottom. The labels are adhered to a liner that has a silicone layer, allowing the labels to be released from the liner and then applied to the container. Conceptually, a roll of p-s labels is analogous to a roll of self-adhesive stamps.

P-s labels are versatile, as indicated by the diversity of user product categories: foods, beverages, wine & spirits, pharmaceuticals, personal-care, household chemicals, and automotive. Whether singularly or in combination, label stock can be paper, film, or foil, and added versatility can be imparted with specialty inks and treatments such as embossing and metallic-stamping. P-s labels are not limited to rectangles or other conventional shapes, either, as customized die-cuts can be ordered easily enough. The labels can be printed with flexography, but if a sharper image is desired and if higher order-quantities justify the upcharge, rotogravure is an option, too. Overall, with p-s labels, there’s a combination of choices that can yield a desired shelf-impact, whether with kaleidoscopic colors, a clear “no-label look,” or anything in between.

P-s labels are applied to rigid packaging, for example, bottles, jars, tubs, and trays, not all of which have flat panel areas convenient to labeling. P-s labels, however, are compatible with contoured areas, lying cleanly, without wrinkling or puckering around the edges. P-s labels also perform well with squeezable containers since they’re able to endure repeated flexing without ill effects.

Apart from the geometry of surfaces is their “feel” (their smoothness and slickness). Glass, metal, paper, and plastic containers differ from one another in that regard; therefore, it follows that the adhesive of a p-s label should be a functional match. Another consideration is the environmental conditions that the packaged product will encounter. Refrigerated temperatures and high-humidity, for example, require an adhesive different than one that might suffice under different conditions.

Regardless of whatever differentiations can be made between p-s and other labeling technologies, they share having to defend their sustainability merits. Source reduction, in particular, challenges all labeling technologies, but none more so than it does p-s. That’s because p-s rolls consist of no fewer than 5 layers: top coat, label stock, adhesive, release coating, and liner.

Even assuming an ideal roll in which all layers have been reduced, the liner and its release coating remain as waste to be disposed of (at an assignable cost), just as the liner remains after self-adhesive postal stamps have been removed. The coated liner that ends up as waste nonetheless is part of the incurred transportation cost. Regarding storage, because the liner increases roll width, space efficiency is reduced.