Types of label adhesives
Label adhesive applications can be divided into three main categories: removeable, repositionable, and permanent. Assigning your application to one of these is the starting point to choosing the right adhesive and will strongly indicate the level of tack the glue should provide. For example, a removeable label adhesive should provide just enough tack to grip the surface at the time of application, without increasing its strength, and will remain in this state until it is removed. Each label type has its own unique functionality and applications:
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Permanent: Unlike removable or repositionable labels, it should be impossible to remove a permanent label without damaging or distorting the label. This makes them ideal for tamper-proof and tamper-evident labels, warning labels including chemical labels, and outdoor labels, more generally. Although such label adhesives are by their very nature more robust than temporary alternatives, the environment, and conditions to which they will be subjected still need to be considered when choosing an adhesive.
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Removable: As mentioned, these labels can be easily removed, leaving behind little or no residue. To achieve this, it’s crucial to balance strength and removability, ensuring the label adhesive’s peel strength is perfectly optimised. Groceries, pricing labels, and promotional stickers are common examples of this application.
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Repositionable: A subset of removeable labels, repositionable labels allow users to remove and reuse, helping to avoid permanent creases, wrinkles, and bubbles. The most common example is sticky notes.
Label adhesive terminology
Its useful to understand the properties of different adhesives and how they impact their performance to ensure the right adhesive is selected for the application. Properties that include:
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Tack: Initial attraction to a surface with minimal pressure. Lower tack adhesives are easier to remove from surfaces.
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Adhesion: Strength of bond between adhesive and surface after pressure. Higher adhesion will make a label more difficult to remove and may result in substrate or label tear.
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Peel: Force needed to remove an adhesive from a surface. Adhesives with lower peel strength being easier to remove.
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Shear: Ability of the adhesive to withstand force applied in opposite directions. Softer adhesives have lower shear strength, higher tack, and may be more likely to tear.
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Temperature: Minimum application temperature is the lowest temperature at which the adhesive will adhere to a substrate. Service temperature is the minimum and maximum temperatures at which an adhesive will maintain its strength.
Other label adhesive considerations
Further items to consider when choosing an adhesive include the substrate surface, as different adhesives work better with materials such as glass, plastic, and metal.
Specific application requirements can also impact the type of adhesive used. For example, in the food and beverage industry, some containers are hot-filled to sterilise the contents, whilst carbonated drink bottles usually expand, putting pressure on the label to do the same. The adhesive used for such applications needs to be suitable for the specific surface, temperature, and provide the necessary accommodation to allow for the label to stretch.
Additionally, environmental concerns increasingly play a part in the label adhesive chosen. For example, the PET drinks industry is moving to a “reuse” circular economy model, whereby alkali washable adhesives allow labels and adhesives to be completely removed from PET bottles before they renter the market.
Value-enhancing adhesives and services for labelling
Using the right adhesive for labelling should be relatively straightforward: identify the material or container to be adhered to, the basic application (permanent, removable, or repositionable), any specific requirements in terms of application or service temperature, as well as other demands such as labels for carbonated containers. Then, start using the chosen adhesive accordingly.
In practice, every application is unique, and each business has a combination of different machinery, label materials, environmental conditions, and performance requirements that require the adhesive to be tested before it is rolled out across production.
This is why we strongly recommend working with a manufacturer that can match either an existing adhesive or develop a custom formulation to meet your exact label adhesive needs - providing both laboratory testing of materials and, if necessary, supporting trials of the new adhesive onsite.
So, if you’re involved in manufacturing, converting, or using labels, why not speak to Beardow Adams and see how our team can help to improve your label performance? Simply send an email to marketing@beardowadams.com or fill in the enquiry form on our contact page.