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Surface Preparation to Enhance Bond of Pressure Sensitive Adhesive (PSA)

August 8, 2019

Preparing your substrate for the best bond possible is crucial when applying a PSA because it helps to ensure the success of the bond.  There are different processes to prepare a substrate for an application.

The process is dependent on:

  • Material
  • Adhesive type
  • Substrate conditions

It’s important not to overlook the surface energy of the substrate.  To create a higher surface energy, it’s important that the surface is clean, dry and rough.

  1. Clean: Start by cleaning the surface of any debris and contaminants.  The standard way to prep the surface is to use a 50:50 mixture of isopropyl alcohol (IPA) and water.  To remove heavier oils, use a degreaser or solvent-based cleaner.
  2. Dry: Working with a dry service is important because it helps to ensure a secure bond.  Having moisture on the substrate will promote a poor bond.
  3. Abraded: Roughing up the surface with sand paper can create more surface energy and provide a slight grip for the adhesive to attach to.   PSA can flow into a rough surface to maximize bond strength based on higher contact area.

If the substrate still has a low surface energy after following these steps, a primer may help.  When picking a primer consult your supplier to find what primer would work the best.  If a primer isn’t an option, a flame treatment, surface roughening or chemical etching could be alternatives that might work.

Bond Strength can be measured by a test method called the Peel Test (Pressure Sensitive Tape Council or ASTM)

  1. Peel Values indicate the bond strength of the PSA to a particular substrate
  2. Initial adhesion indicates how well a PSA has bonded to a substrate after a short period of time, usually seconds or minutes
  3. Ultimate adhesion refers to a PSA’s bond strength after 72 hours