We occasionally hear from customers who comment that their labels are not “sticking” properly to their product containers. The reasons for this can be quite diverse, but there are some things to explore if this happens to you:
First, it’s important to understand that poor adhesion is not normally the result of a “bad batch of material” during the label production process. Yes, it has very rarely happened over the many years we’ve been in the label printing business, but the material vendors have definitely lifted their game. Also, if your labels were the result of a bad batch, we’d probably know about it very quickly – as many customers would be affected.
Now we get to the most likely causes of poor adhesion, which fall into three major categories – container type, surface corruption, and application method. Let’s start with container type…
For good adhesion to occur, labels must have a good surface to adhere to. Plastic, glass, and good flat box materials are excellent targets – because they offer a smooth consistent surface for the label to stick to. Conversely, corrugated cardboard, fabrics, or other rough surfaces may not achieve the same level of “bond”. We always highly recommend testing (using samples we are happy to provide) before making any assumptions.
Even if your containers are receptive to adhesive labels, surface corruption is a big contributor to problems with labels. For the adhesive to achieve a good bond with the container, the surface needs to be clean and free of any external influences that could affect adhesion. Dust and grime may not be very common, but anything that gets between the label and the container is likely to affect the result. Also if you normally fill your products before applying labels, it’s not unusual for some of the product to end up on the outside of the container – so it’s critical to make sure the container is properly cleaned before attempting to apply labels. And even a shiny new batch of bottles or jars arriving from the vendor can have invisible curruption as a result of the manufacturing process, so all containers should be properly cleaned, regardless of how pristine they may appear.
Application method can also affect adhesion – i.e. the way you actually apply the labels. Machine applicators are usually very good, because they minimize the amount of physical contact between human beings and the application process, whereas hand application relies on somebody picking up each container. When this occurs, skin oils can easily be passed onto the container surface – even though you’ll never see it. Even a small amount of skin oil (or moisturizer) on the hands can create enough of a barrier to prevent proper adhesion. We recommend wearing cotton gloves to minimize the chances of this kind fo incidental corruption.
One last tip – if you do encounter adhesion challenges and/or want to do some testing of particular label materials on your containers, keep this in mind… most label materials are deliberately designed with adhesives that take some hours to properly “set”. This allows the customer to reposition any labels that were crooked or badly aligned – a feature the material manufacturers call “short term repositionability”. That’s a mouthful, but it makes more sense for labels to have some wiggle-room during application than if they used super-glue and your first attempt was your only attempt. We recommend applying the test labels one day, then leaving them overnight before forming any conclusions.
Also, if you begin to see “bubbles” appearing in your labels once the adhesive has had time to set, this could be a sign of surface corruption too – because if the material were at fault then it’s much more likely to be uniform across the whole label, not just small areas. Such bubbles might be a good clue that something is getting onto the surface – even if it’s not visible to the naked eye.
So, poor label adhesion is not something we encounter very often at all, but in almost all cases we find it’s due to some physical issue – either with the containers themselves, surface cleanliness, or the application method being employed. We’re happy to help explore these further with you if necessary, but in our experience it’s almost never a result of “bad labels” – and reprinting the labels does not solve the root problem.