Here's a short guide to label "memory" and how to avoid problems related to this material property.
All labels have a “memory”; meaning that if they are stretched or distorted in any way from their original dimensions, they will try to return to their original shape.
Different materials have different strengths of memory; for example, our polyester labels all have stronger memory strengths than our paper labels.
Label memory can cause problems if you need to apply a label to an uneven surface – particularly cylindrical objects (such as tubes and bottles) or around a tight corner. The label will try to return to a flat state and so fights against the adhesive; if a label’s memory is stronger than the adhesive, the label will begin to return to its original state and its edges will curl up or the whole label will peel off entirely.
So how can you avoid problems with label memory?
- If you have to label an unusual surface, make sure you choose a label material with a low memory strength, such as paper labels.
- Alternatively, make sure you choose a label with a high strength adhesive, such as high tack labels.
- You could even try to combine the two and choose a label such as our polyethylene labels, which are more flexible than our polyester labels (giving them a lower memory strength) and have a high quality marine standard adhesive.
- You could also try to improve the bond formed by the adhesive on a label. All adhesives have an initial tack and an ultimate adhesion; the initial tack describes how well the adhesive sticks to a surface on initial contact. Once a label has been applied, the adhesive continues to cure and strengthen until it reaches ultimate adhesion (the strongest bond that a particular adhesive can achieve). In order to speed up the curing process you could try applying extra pressure when sticking the label onto an object or make sure that the label is applied and/or stored at a higher temperature. This will allow the adhesive to strengthen faster than usual, meaning it is more likely to have formed a strong bond by the time the memory of the label starts to work against the adhesive.
- Finally, if you are applying a label to a cylindrical object, you could try choosing a larger size of label that will overlap itself when wrapped around the object. Labels will usually start to curl at the edges and so sticking one edge of a label over another will help to prevent the label peeling off. If there isn’t a large enough label to wrap around a particular object, you can always try using two labels and overlapping them over each other.