Types of Label Adhesive
Monday, July 14, 2014 1:53 PM
When considering what sort of label you’ll be using for your product, it’s important to think about how well you actually want your label to stick to your product and what kind of environment your product will be in. The different types of adhesives work well for specific applications and not well for others. Which adhesive to choose depends on the conditions your label will have to endure. the required longevity and it’s purpose.
There are four basic criteria of performance that an adhesive is evaluated on:
• Printer Converting – Die cutting and stripping.
• Initial Tack – How well the label sticks initially.
• Long Term Bond – After the the adhesive is set, how well the label performs.
• Consumer Use – Will the label will be exposed to; cold, water, heat, abrasives.
Pressure-sensitive label adhesives are commonly made from water based acrylic adhesives, with a smaller volume made using solvent based adhesives and hotmelt adhesives. The most common adhesive types are:
• Permanent – Typically not designed to be removed without tearing the stock, damaging the surface, or using solvents. The adhesion strength and speed can also be varied. For example, full adhesion can be nearly instant, or the label can be almost removable for a short period with full adhesion developing in minutes or hours (known as respositionable adhesives).
• Peelable – Adhesion is fairly strong and will not fall off in normal circumstances, but the label can be removed relatively easily without tearing the base stock or leaving adhesive behind on the old surface. The adhesive is usually strong enough to be applied again elsewhere. This type is frequently known as 'removable'. There are many different types of removable adhesives, some are almost permanent, some are almost 'ultra peelable'.
• Ultra-peelable – Designed principally for use on book covers and glass, when removed these adhesives labels do not leave any residue whatsoever. Adhesion is weak and only suitable for light duty applications. Normally these labels have very little adhesion to anything once they've been removed.
• Freezer or Frost fix – Most permanent and peelable adhesives have a service temperature limit of -10 degrees Celsius, whereas freezer (otherwise known as frost fix) adhesives have a service temperature -40 degrees Celsius and are suitable for deep freeze use.
• High Tack – A type of permanent adhesive that exhibits a high initial grab to the application surfaces, and is commonly used at higher coat weights to enable labels to adhere strongly to difficult, rough or dirty surfaces.
Before a label adhesive is chosen, many factors must be considered. These include the size of the label, the texture of the façade to be labeled and the mobility level required; some, such as retail labels, must be removed at some point, and others, such as shipping labels, can be left intact indefinitely.
If a label is attached with the intent of it never being removed, or if only a solvent would remove it, it is called permanent. In some cases, before a label attains permanent status, it has a short period where it can be moved. These labels are often referred to as repositionable.
If a label will be exposed to a very moist environment, such as a freezer, refrigerator or cooler, water-based adhesives are not practical. They break down, and the labels can fall off the products, regardless of the surface to which they are applied. Water-based adhesives should only be used in dry environments.
Adhesives mainly composed of rubber are preferred for their tackiness. They are prone to failure when exposed to UV rays over extended periods of time. If the labels will not be exposed to sunlight, this type of adhesive works fine.
A peelable label is just that: it can be peeled off a surface ease. The surface exterior is not marred, and no adhesive residue is left behind. This type of label can normally be used two or three times and not lose its stickiness. An ultra-peelable label is popularly used on book jackets and glass, where no residue is acceptable. These labels can only be used once before the adhesive is gone.
For labels that will be exposed to freezing temperatures, freezer or frost fix adhesives are preferred. They withstand extreme cold without peeling or cracking. If a label is required to securely stick to a dirty, misshapen or rough surface, a high tack glue is needed. Static cling labels do not use a traditional adhesive but cling to very smooth surfaces such as glass using only a static charge.
If you have any questions about what kind adhesive would work best with your labeling project, please feel free to call us. We’re happy to help and point you in the right direction!