How to Choose the Right PSA

by Phil Taylor, Vice President of Sales

It was not too long ago that we licked our postage stamps before we stuck them on our envelopes. Now, for what little postage we send through the U.S. mail, our stamps are peel-and-stick. In fact, in the past 20 years or so, PSAs have taken on much tougher fastening and bonding applications. PSAs have replaced rivets and screws on machines, automobiles, and toys. In many ways, PSAs have made small, hand-held electronics possible. PSAs have become part of our daily lives. We use PSA to permanently affix and seal your cell phone lens. And we use PSA to temporarily stick a reminder to our refrigerator door.

It might be a little intimidating to try to choose from the multitude of PSAs and manufacturers of these products that are out there today. At Marian, we can help you select the best double-faced tape or transfer adhesive PSA for your application. We would be happy to help you with your PSA selection, and you can go to www.marianinc.com/psasearch to get started.

In the meantime, here are the things you should consider:

• Fasten, permanently bond
• Fasten, temporary bond
• Fasten, assembly aid (temporary)
• Vibration damping
• Seal against air & gas
• Seal against liquids or moisture
• Seal against dust and foreign particles
• Separation (or barrier) between dissimilar surfaces or materials
• Fill a gap or take up space
• Absorb vibration or shock
• Needs to be optically clear
• Block light
• Electrically conductive
• Thermally conductive

What two surfaces are being joined together?

Most materials fit into one of the following categories:

• Paper
• Metals (steel, aluminum, copper)
• Treated or powder coated metals
• Rubber
• Foam or sponge
• Glass, ceramics, or painted surfaces
• Cloth
• Low surface energy material (like polyethylene and polypropylene)
• Plasticized vinyl (soft, flexible)
• Low out-gassing plastics (like rigid vinyl, ABS, acrylics)

In addition to identifying the nature of materials being joined, it is also important to qualify the nature of the surfaces. Are they porous or highly polished? Are they clean? Free of dust, lubricants, or other contaminants?

What thickness or thickness range of the double-faced tape or transfer adhesive is important to your application?

When it comes to PSA a rule-of-thumb is “thinner is better.” You need full surface contact on both surfaces and not much more. But you may need a double-faced tape to help take up space, create a barrier, or absorb vibration. You may have a “stack height” concern for your overall lamination.

What is the relative temperature of your product’s application?

And, what are the worst-case temperatures (both high and low) of your application? All PSAs should be applied at ambient room temperatures. But we need to know what your end product’s environment will be like.

And, if so, what are they? Or what is their nature? Acidic? Alkaline? Liquid? Powder?

How important is shear strength to your application?

Maybe you need a double-faced tape or transfer adhesive with high shear strength. Imagine if you hung a weight from a double-faced tape that had been stuck to the wall of your office. In this application, gravity would exert a shear force on the PSA. The PSA would need a high shear strength.

How important is peel strength to your application?

You may need high peel strength for a permanent bond or low peel strength for a temporary bond.

Imagine if you hung a weight from a double-faced tape that had been stuck to the ceiling of your office. In this application, gravity would exert a peel force on the PSA.

Rank all of the above issues in importance to you and your application.

With a discussion of these seven simple questions, your Marian sales or customer service representative will be able to help focus your choices of products to the best and most cost-effective products. We look forward to hearing from you the next time you have an application that involves a PSA!