Label Adhesive Guides: Type and Properties

Depending on different usage conditions, choosing the suitable adhesive becomes more challenging – especially when you want the label to "work" well in other conditions. In this article, you can find information on glue types, characteristics, and properties.

Types of adhesives

There are three main classifications of adhesives to know: Permanent, Removable, and Repositionable.

1. Permanent: This is the majority of labels adhesive because they work for most label applications and tend to be the most budget-friendly. Since it creates a strong bond with the container they are applied to, removing the labels can damage the labels or adhesion surface.
2. Removable: Labels with a removable adhesive can be removed after a period of time without damaging the label or the adhesion surface. With this characteristic, this type of adhesive is ideal for temporary marking items, in-store coupons, and limited-time promotions. However, be aware that temperature can affect the stickiness and removable capacities of labels with this adhesive type.
3. Repositionable: Designed for short-term removability in cases where the labels need to be repositioned or reapplied. This adhesive can save you time and resources in the long run when labels need to be removed for repositioning purposes (e.g. the label is bent on the adhesive surface) or reapplied to another surface without losing much adhesion. The time between initial application and permanent bonding varies depending on the formulation. Depending on which type of repositionable adhesive is used, it can eventually become permanent.

Adhesive properties

The information above helps you understand the right type of adhesive that works for the application you are using. However, within the same adhesive, there are still distinct characteristics. Therefore, you need to know more about the basic characteristics to determine the most suitable adhesive you need.

1. Initial tack: represents the immediate holding power on contact with the specific surface. If the initial tack is low, you can easily remove the label without leaving adhesive on the surface. The adhesion of the label will increase over time (This is the difference between removable and repositionable). On the other hand, adhesives with high initial tack will bond to the surface more quickly.
2. Ultimate adhesion: the maximum holding label will achieve as the adhesive fully bonds to the surface. How long it takes for an adhesive to gain ultimate adhesion varies and depends on factors like the adhesive’s stiffness, the roughness of the receiving surface, and environmental conditions. Depending on those factors, it can take anywhere from 2 – 24 hours for ultimate adhesion to happen.
3. Shear resistance: label adhesives with low shear are soft and can flow into the surface they’re applied. They also have a higher initial tack but can split apart under stress. A higher shear adhesive is firmer so it doesn’t flow as well into the surface, resulting in a lower initial tack and making it less likely to split apart under stress
4. UV resistance: If your labels are exposed for a long time to ultraviolet (UV) rays, they may be susceptible to color changes or weakened adhesion. Select a U.V.-resistant adhesive in cases where your labels will be exposed to U.V. light on your end, or if your labels will be exposed to U.V. light during the printing process (e.g. when a U.V. laminate or coating is applied to your labels) to minimize these effects.
5. Solvents resistance (water, alcohol, petrochemicals, plasticizers): determines the ability of labels to withstand exposure to the solvents. It is necessary to consider the labeling surface, as well as the environment where the product will be used.
6. Minimum application temperature: When an adhesive is not designed for a frozen environment, it will stiffen and lose its adhesion as the temperature decreases. Most adhesives can be used at a minimum temperature of 4-10oC Celsius before they achieve a full bond. The adhesives can work in freezing can withstand temperatures up to -50oC
7. Service temperature range: The temperature range at which the adhesive can work well after the label has been applied and achieve the ultimate adhesion. Most pressure-sensitive adhesives have a service temperature range of -50oC to 90oC with paper stock or up to 150oC with film label stock.

Conclusion: With the above information, you can make initial choices about the right adhesive for the labels you need. In the next article, Ricoh will share more specifically about common chemicals in glue: Acrylic glue, and rubber-based glue so you can understand and make a more perfect choice. For more specific consultation on the type of label and glue suitable for your product application, you can leave information or contact email [email protected].

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