Choosing the Right Label Adhesive

Package labeling is a quickly evolving field that demands constant attention to shifting trends, competitor design decisions, and consumer preferences, as all of these factors can affect the sort of labeling attributes that the industry demands. As desires for increasingly advanced label properties drive research and development into new labeling technology, it is important for packaging designers and engineers to clearly understand the various aspects of package labeling well enough to recognize where a competitive advantage might reside.

Because of the diverse nature of packaging applications in various markets, from food and beverage packaging to health and beauty packaging, no one set of label properties will deliver the best performance and aesthetics in every case. Careful consideration should be made regarding every aspect of a labeling application to determine how to best balance functionality and visual appeal. It is important to consider more than just a label's facestock when choosing labeling materials.

While they may not often be consciously noticed by consumers, adhesives play a crucial role in label functionality, performance, and appearance. For this reason, this article will focus on some of the factors to consider when deciding what adhesive-coated label stock to use in your package labeling application, giving you the knowledge to make informed decisions and make products stand out subtly from competitors.

Know your application

As is the case with many products and components, not all offerings in the adhesives world are created equal. There are different adhesive formulations at different price points intended for different uses, making a thorough understanding of your application the most significant key to success in choosing an adhesive. In packaging applications, adhesive requirements can mainly be grouped into two categories: performance requirements and aesthetics requirements. Consider both of these for your application to be sure you are receiving not only a facestock that makes sense, but an adhesive that will deliver what you need as well.

Adhesive performance

One of the first things to consider from a labeling adhesive standpoint is application surface properties. Will the label be applied to a smooth surface or a textured surface? Depending on the composition of your product packaging, will an adhesive need to be conducive to use with low- or high-energy surfaces? With the rising prevalence of various plastics in packaging applications for food, beverage, healthcare, cosmetics, cleaning products, and more, it is important to know the chemical composition of the packaging to ensure an adhesive will stick to the package surface for an appropriate length of time. In addition to application surface properties, consider the shape of the packaging and related needs for conformability as well. In the case of a curved container, such as a lotion or shampoo bottle, conformability is important to avoid tunneling and to ensure label adhesion and longevity.

The next thing to consider from a package labeling performance standpoint is desired levels of repositionability, removability and permanence. Repositionability is determined by the aggressiveness of an adhesive upon initial tack, which can determine whether a label can be removed and reapplied if not positioned perfectly the first time. If labels are being applied to packaging by hand or in small quantities, having a level of repositionability that leaves room for error may be desirable. If the label is being used as part of a package closure system, such as baby wipes or some food packaging, removability is a function of the application. Additionally in some applications, there may be a need for a label to be completely removable from a product, revealing under-label directions or maintaining the clean look of a glass surface, and thus ease of removability may be necessary.

On the other hand, however, there are a number of applications where you might want a label to go on and stay on permanently. This requires a high-performance permanent adhesive—something that an increasing number of manufacturers are requesting. Permanence is especially important with applications that might be plagued by counterfeiting, such as spirit labeling, high-end cosmetics, pharmaceuticals and prescription drug labeling, electronics, games, ink cartridges, and more. Counterfeiting in these realms can not only tarnish brand image, but in some cases have potentially deadly consequences for consumers as well.

Choosing a label that is not easily removed and that may even have built-in anti-counterfeiting measures is important in these applications. "Void labeling," for instance, involves an adhesive splitting from the film when a label is removed from a substrate, leaving an imprinted "void" pattern showing undeniable evidence of tampering. Regulators and law enforcement officials are constantly seeking ways to eliminate counterfeit materials to stay ahead of increasingly sophisticated counterfeiters. Product manufacturers can implement different levels of security in product labeling to protect their brands, such as hidden graphics that require special equipment to recognize and reproduce or taggants/markers that are integrated into the adhesives or printed onto labels. Because of the complexity of designing security labeling to protect labels, each measure is dependent upon the product being sold.

Adhesive formulation and application surface properties are not the only things that affect label longevity. It is equally important to factor in the environment in which a product will be labeled, transported, stored, and used to ensure that the adhesive you choose possesses the proper durability characteristics. Consider extreme temperatures, or moisture and humidity for instance. Is your packaging going to be subject to the cold of a freezer or winter transportation? Will it be exposed to high heat or sunlight? If it is exposed to sunlight, does it need UV-resistance to avoid being compromised?

Moisture and humidity might cause issues with labels on products such as personal care items that might reside in bathrooms, or food products residing in refrigerators or other environments. Products in these environments might also suffer tunneling and lifting of labels due to direct water contact—a consideration especially important with beverage packaging applications. Remember that various adhesive formulations respond differently to these conditions, and they should not be overlooked.

Chemical resistance is important as well, especially for household cleaning products or cosmetics that could interact with adhesives to compromise their functionality. It is important to know how all aspects of a label will react when coming in contact with compounds that may be stored or used nearby, such as gasoline, cleaning solutions, oil, and so forth. Adhesive solutions exist that stand up to all of these conditions, and proper foresight regarding end-use environmental conditions can mean a greater likelihood of success in package labeling.

A final consideration from a performance standpoint is regulatory compliance. Does a label and its adhesive need to be direct food-contact compliant as specified by the U.S. Food and Drug Administration, for instance? Are there other application-specific certifications or performance properties that are necessary to achieve, such as anti-leaching in pharmaceutical or health and beauty applications? Factor these concerns into any adhesive decisions for your labels.

Aesthetics

It is well known that visual appeal can play a key role in purchasing decisions. As every aspect of packaging design comes under scrutiny as brands compete for consumer attention, remember that an adhesive can contribute to an overall packaging look, not just the facestock.

Consider adhesive clarity, for example. Many high-end products in the food, beverage/spirit, and cosmetic markets are now being packaged with a sophisticated "no-label look" in mind. In order to accomplish this, it is necessary to find the right clear film facestock and optically clear adhesive combination to create the desired label. Depending on the application, not just any clear adhesive will do, either. For instance, in the food and beverage industry where showcasing a product by way of a no-label look is gaining in popularity, it might be prudent to use an advanced clear adhesive with special properties to resist the whitening that many clear adhesives exhibit when exposed to water.

In response to these needs for uncompromising clarity in applications that may still have high performance demands, one of the newest developments for package labeling is an optically clear, permanent, secure adhesive. Using a highly engineered adhesive solution such as this ensures sacrifices do not need to be made on the aesthetic or performance side of package labeling, allowing the best all-around label properties.

Best value

When it comes to balancing performance and aesthetics, it is hard to find a higher-stakes application than consumer package labeling. When designing product labeling, be sure to ask yourself the right questions about adhesives and other labeling components, and know your application needs thoroughly. This will give you the best chance of creating product labeling that will look great for the life of your product.

Doing your research can also help you reduce design time, production costs and overall time-to-market for your product. There are high-end, clear, permanent, aggressive, non-water whitening, exceptional adhesives that can deliver all the functionality you could ever need, but there are also more economic adhesives for short run jobs that may suit the demands of your application—find the right balance of adhesive properties and affordability for optimal results.

Finally, there is no better way to account for all aspects of your package labeling application when making material decisions, especially those that involve technical components like adhesives, than to rely on experts who know it best. Bring your questions and concerns to suppliers to ensure you're well equipped to label your product packaging in a way that will not only catch consumers' attention, but meet their expectations for performance well after purchase.

About the author—Kim Hensley is the product manager – durable films, MACtac® Roll Label and has served MACtac's roll label commercial area for more than 15 years. She is responsible for managing all aspects of MACtac's durable film product line. pP