In the design stage, your team considered the properties of the adhesive to determine if it was the right kind for your project.

While your choice of adhesive is critical, it’s equally important to make sure that a poorly prepared surface doesn’t thwart your project. In the end, layers of dirt, wax, grease and other contaminants can work against you. So will failure to consider low-energy surfaces that are difficult to bond. Any of these can diminish the performance of your chosen adhesive.

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As you were choosing the right pressure sensitive adhesive, you were looking at several properties to make sure it was the right fit for your project, including:

• Surface energy of the substrate
• How the adhesive performs and responds to environmental conditions
• Adhesion strength and its response to pressure: Tensile, shear, cleavage and peel

What gets overlooked in the planning is proper surface preparation. As your team selects the right pressure sensitive adhesive, you’ll also want to factor surface prep to make sure it reaches maximum surface contact to form the bond that you expect from the tape.

Factors that maximize surface contact with pressure sensitive adhesives

To get maximum performance from your pressure sensitive adhesive, these three elements are critical:

• The surface needs to be dry and free of contaminants. Any grease, dust and grime that clings to the surface of your substrate gives your adhesive less surface area to adhere to, so it can’t reach its maximum adhesion.
• Application of firm pressure to increase contact of the adhesive with the surface.
• Dwell time, because surface contact will allow adhesion values to build.

According to 3M, most PSAs build ultimate bonding strength over time:

• 50% of ultimate bonding strength after 20 minutes
• 90% after 24 hours
• 100% after 72 hours

Need to reach full strength more quickly?

• For certain adhesives, you can achieve ultimate bonding strength faster by exposing the bond to higher temperatures.

As you design your application process, your Evans Evco representative can provide the technical expertise on 3M adhesives so you can choose the right materials and the right processes.

How to prep surfaces before applying pressure sensitive adhesive

When your chosen adhesive doesn’t perform as expected, a common culprit is a lack of surface preparation.

Surfaces can be deceptively dirty. Even a miniscule layer of fine dust or dirt will interfere with surface contact of your adhesive. When dust and dirt reduce surface contact, the pressure sensitive adhesive can’t and won’t reach full bonding strength.

Considering that the tape was selected for a specific strength and set of properties, it’s important to make sure it reaches its full potential by having full contact with the surface.

You’ll want to check the technical information of your adhesive as well as your substrate, but the following offers general guidance in surface preparation before applying 3M VHB tapes and other pressure sensitive adhesives.

• Most smooth surfaces: Before applying tape, clean the surface with a 50-50 mixture of isopropyl alcohol and water. Once the surface is dry, apply the tape with firm pressure to maximize surface contact.
• Oil and grease: First, clean the surface with a solvent or degreaser, then finish with an application of the alcohol-water mixture.
• Heavily soiled or oxidized surfaces: Apply abrasion followed by cleaning with the alcohol-water mixture.

Preparation of special surfaces

Dirt isn’t the only factor that can create difficulties in bonding. Surfaces that are porous or have low surface energy often need additional preparation before applying the adhesive.

• Wood, other fibrous or porous materials: Applying a sealant, such as paint or polyurethane sealer can create a unified surface that allows maximum surface contact.
• Plastics and paints: Priming the low-energy surface with an adhesive promoter can be used to improve contact with the surface. When needed, abrasion can also help create more surface area for the adhesive.

Need guidance on surface preparation for your custom adhesive-backed converted material? Your consultant at Evans Evco has the technical expertise on all things adhesive, so you can maximize the performance of your converted pressure sensitive tape application.