Pressure sensitive adhesives are adhesives that require no solvents or heat to be activated. There are three main types of adhesives that are known as permanent, removable, and repositionable and each of these have their own unique properties.
Permanent labels are the most budget friendly. They work for most label applications and they create a strong bond with whatever they are applied to. Due to this removing the label may damage whatever surface it was applied on.
Repositionable adhesives are adhesives that can be removed in the short-term and reapplied. A repositionable label that is applied crooked or not to your liking can adjusted quickly and easily.
Labels with removable adhesive act just how the name leads you to believe. They can be removed for a certain amount of time after they have been applied without damaging the label or whatever surface it was applied on. However, it should be noted that temperature can affect the integrity of these labels’ capabilities.
In addition to these broad types of pressure sensitive adhesives, label adhesives also have varying qualities within these categories that separates them even further from one another.
This is the initial stickiness or grip that a label adhesive will have upon making contact with a surface. Low initial tack means there will be low adhesion allowing for an easier removal whereas high initial tack brings a higher level of adhesion. Low initial tack will build up adhesion over time when not removed.
This is how well the label adhesive adheres to a curved or non-flat surface. Label adhesives with good mandrel holds will not flag, which means the edges won’t fold up.
Label adhesives with low shear have a high initial tack but they are soft and can split apart easier. A label adhesive with high shear is stronger and less likely to tear apart easy but will have a low initial tack.
This is the label adhesives ability to not lose adhesion when exposed to solvents such as water, alcohol, plasticizers, petrochemical solutions, etc.
This is the maximum amount of adhesion that an adhesive can reach after being applied to a surface. Ultimate adhesion usually takes anywhere between 2 and 24 hours and it all depends on factors such as the stiffness of the adhesive, the condition or feel of the surface it is being applied to, or environmental conditions.
Labels exposed to U.V. light for long periods of time are at risk for color change or adhesion decay. Labels that are exposed to U.V. light whether it is through their use or during the printing process should have some level of U.V. resistance.
This is a label adhesives ability to stay bonded to a surface in temperatures below normal.
Minimum Application Temperature
When an adhesive does not have cold flow and isn’t designed cold temperatures it will weaken as the temperature drops. The minimum application temperature for these types of adhesives is around 40 to 50 degrees Fahrenheit.
Service Temperature Range
This is the temperature range a label adhesive will still function in once it was has reached ultimate adhesion.