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Adhesive 201: Beyond Permanent or Removable

Usually when companies talk about adhesives its one of two things: permanent or removable. The truth of the matter is that there is a lot more nuance. Here are some terms to help you better understand the fine points of adhesives..and why you should care about them.

Initial Tack
This is the degree of stickiness when a label is first applied to a product.

Why this matters: Automated label applications want labels that will grab and hold quickly so they don’t fly off. Hand application can be the other extreme. Ever try to get a label placed just right only to have it stick horribly askew? If the adhesive has low initial tack, there is a level of forgiveness that will help you lift clean and re-place the label correctly.
Flow Out
The capacity of an adhesive to spread, filling in the hills and valleys on the surface of the printed or non-printed substrate.

Why this matters: After the initial tack period, the adhesive begins to settle. Some adhesive flow a lot–this is good for getting a strong bond on irregular surfaces. The downside is that they can be somewhat oozy–making them more of a mess to deal with. Others are relatively clean, but will only work on comparatively smooth surfaces. Getting the correct flow out for your needs will affect application and ultimate adhesion. Speaking of which…
Ultimate Adhesion
The mature or final bond achieved by adhesive to any flexible or rigid substrate.

Why this matters: After the flow out, the adhesive settles on its ultimate adhesion strength. Different adhesives take different amounts of time to reach this stage. Your time from application to usage will be important to consider. This is also where you learn that there are different levels of permanent. Some which will fit your needs better than others.
Application Temperature
The temperature of a substrate or label material at the time the label will be applied. All adhesives have a minimum application temperature rating. Temperature can be a factor in the design of labels that will be used in hot or cold environments.

Why this matters: The temperature range at which labels can be applied is usually much narrower than the overall temperature band once the label has achieved ultimate adhesion. If labels are applied outside this temperature, they will often fail. If you know what temperature the labels will be applied at, this can be successfully avoided.