While different types of label adhesive may appear to do the same job, maintaining maximum productivity and minimum label spoiling means understanding the properties of different types of glue.

It was said by the upper echelons of Victorian society that “a good servant is one who is able to remain invisible.” The same can be said of a good adhesive. It is not just how it performs for the consumer, but more its ability to remain undetected. However, from a brewer’s perspective, an understanding of how an adhesive performs is essential, in order to ensure that the right product bond is achieved.

Adhesive usage depends on the type of bottle and the label stock. In the bottling industry, the importance of maintaining label integrity is universal. Adhesive manufacture is completely consumer-led; right from the Research and Development phase. National Adhesives is one company that has invested heavily in R&D, developing products to overcome a range of industry challenges.

Property development

Different adhesives offer different properties. Water-based glues and self-adhesives are predominantly used in the glass bottle labelling process, but the use of hot melts is on the rise. Water-based wet glues offer optimum bond between glass bottles and paper labels. The key component of National’s wet glues is casein - one of the proteins found in milk. Casein offers a host of unique properties. As a natural polymer, casein fulfils all food contact requirements for the beverage industry and also has the advantage of biodegradability over synthetic counterparts. In addition, casein endows water-based adhesives with all of the high-performance characteristics necessary to ensure optimum paper-to-glass bond, as it works very well on both cold and wet surfaces.

Flash pasteurisation is increasingly being employed instead of tunnel heat treatment and the result is colder, glass bottles which condensate quickly in high humidity. The casein-based adhesive works effectively under such conditions, enabling immediate paper label sticking. Other adhesive technologies can be used, but to work effectively bottles need to be dried first, which ultimately means longer production times and extra energy costs.

The right chemistry

National Adhesives’ ETICOL products are among the World’s top performing casein-based wet glues. The range incorporates a family of adhesives offering different customer requirements. ETICOLs comprise paper flexibility and work on a variety of label stocks - an important commercial concern, as brewers often have various label suppliers.

ETICOL 700 is a product that works well on all types of glass bottle applications. It offers good all-round performance characteristics, such as condensation water resistance and tack. ETICOL 701 also offers similar properties combined with a fast set speed. This particularly minimises label slippage and damage for non-recessed bottle applications; in which bottles are pressed against each other on the production line.

Higher-grade adhesives are typically used with labels that are more complex. This is of particular importance to spirit distilleries and sparkling wine producers - who often use polished coatings on paper labels and distinct bottle shapes. The more a label has been treated, the greater the adhesive requirement. National Adhesives has two high-grade glues in its range. ETICOL 702 offers a very high level of tack, and superb condensation water resistance, while ETICOL 706 offers excellent ice water endurance. In addition to enhanced flagging prevention and metallic paper adhesion, these glues also provide labels with greater storage longevity, when stored in high humidity conditions.

ETICOL products have varying chemical compositions, in addition to different concentrations of casein. The ETICOL 700 range is heavy metal-free, which means less contamination in food/beverage containers and in wastewater during the washing and re-filling process.

Environmental compliance is a major manufacturer concern. The efforts that manufacturers make in the context of corporate social responsibility, carbon emissions, water and energy conservation have the power to affect a client’s buying decision. The higher the content of heavy metals and the higher the amount of material with limited or slow biodegradability, the harder and more costly the water treatment process becomes for breweries that use returnable bottles.

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