The Basics of Pressure Sensitive Adhesive Tape

Have you ever wondered how tape works?

When you think of the word tape, you most likely imagine pressure-sensitive adhesive tape, which ranges from your everyday household tape to IV attachments used in hospitals.

Strouse has spent over three decades buying, storing, processing, and working with pressure-sensitive adhesive tape. If you’re among the many people wondering what pressure-sensitive tape is and how you can use it, we’d like to share what we know based on experience.

Once you’ve learned more about pressure-sensitive adhesives, you’ll be ready to take the next step in your project using your knowledge of adhesive tape, how it's manufactured, and how to choose a suitable one. 

What is Pressure Sensitive Adhesive Tape?

Pressure-sensitive adhesive tape (PSA) can be a strip of cloth, paper, metal, or plastic so long as the material has permanently tacky adhesive on at least one side. 

Though it’s not necessarily heat-activated, PSA must adhere at room temperature permanently. PSA is pressure activated and only sticks if you compress it.

Pressure-sensitive adhesive differs from other adhesives because it doesn't require much effort to adhere, whereas other tapes may need water, solvent, or heat to activate the adhesive. In addition, it shouldn't change phases, a.k.a. shift from a liquid to a solid.

Between glue and adhesive tape, the tape doesn’t need to dry or cure, and there are no follow-up requirements. 

In adhesive, you may sometimes hear specific terminology:

• Polymer refers to a large molecule with many atoms. The atoms are connected in a chainlike fashion. 
• Viscoelasticity refers to the material’s viscous and elastic properties. Viscosity is related to the amount of resistance against linear strain, whereas elasticity is related to how much stress it can endure and still return to its original shape.  

In short, pressure-sensitive adhesive tape (also referred to as PSA, self-adhesive, and self-stick adhesive) is a polymer with some level of viscoelasticity. The tape is sticky with a peel that protects the adhesive until you need it to bear weight. 

Engineers use pressure-sensitive adhesives daily because of their load-bearing properties, which means strong adhesive bonds can carry significant weight. 

Scientists, engineers, and everyday consumers find uses for PSA tapes daily. As adhesive technology increases and grows, people will find this type of tape more manageable and less costly than traditional solutions for fastening. 

What is an Example of Pressure Sensitive Adhesive Tape? 

Pressure-sensitive adhesive tape can be used for practically anything.

Box-sealing or packing tape, masking tape, duct tape, double-sided tape, electrical tape, and even the athletic tape you’d see on hockey sticks or baseball bats are all variations of PSA tape. 

PSA tape can be used to bond, shield EMI/RFI, manage heat, mask off areas, protect surfaces, dampen vibration, suppress sound, seal, gasket, and numerous other solutions. Yet, it’s far different than heat-activated adhesives, which require heat to make them sticky. 

PSA tape doesn't take much pressure to activate. You can find it in all industries, especially within the healthcare industry, with stick-to-skin tape and wound-care solutions.

How Does Pressure Sensitive Tape Work?

Different types of adhesive tape are generally separated by their design and the function they serve.

Tapes are processed using adhesive transfers, which occur when the sticking solution transfers from one substance to another. 

Think about when you pull away the waxy paper of an envelope, which isn't permanently stuck to the adhesive. The adhesive stays on the original envelope or bag, and when you press down, it transfers adhesion to another material. This transfer process is a single-coated adhesion.

TRANSFER TAPE

Transfer tape will transfer adhesion to two different surfaces. It brings the adhesive material to one surface, leaving the other vacant. 

Transfer tape is similar to a clean line of glue that you would place on a surface. The tape is adhesive coated on a removable liner which means it’s sticky on both sides. This design allows for it to cling to odd surfaces, contour around edges, and be more flexible. However, it is not as sturdy as double coated tape, as mentioned below. 

Transfer tape is challenging to use and requires some practice and skill. 

To function at its highest potential, the tape should have an adhesive that is more difficult to remove on one side, allowing the transfer tape to unwind appropriately. 

DOUBLE COATED TAPE

When you think of double-coated tape, think of double-sided tape. Essentially it’s pressure-sensitive adhesive with adhesive on both sides of the tape. The main difference between double coated tape and a transfer tape is the addition of a carrier between the layers of the adhesive. 

Double-coated tape is used for plastic films, tissue, and nonwoven materials. In addition, you can find double-coated PSA being used as either laminate or carpet tape. 

Companies coat two sides of a carrier material with adhesive to create double sided tape. These companies then wind the adhesive roll with a release liner to prevent the tape from sticking to itself, often painting the liner with a silicone release agent. 

SINGLE COATED TAPE

Single coated tape occurs when you have an adhesion on only one side of a material. Manufacturers keep the adhesive untouched using silicone-coated release liners, often called the web or face stock. 

Single-coated tapes are commonly self-wound and have paper or film release liners. Sometimes a single-coated tape, like filament or duct tape, will have woven cloth or glass strands to reinforce it. These tapes are paired with adhesive systems that have a rubber base. 

Most tapes qualify as single-coated adhesive tapes. 

Electrical tape, masking tape, carton sealing tape, and most medical tapes qualify as single-coated tapes. Single-coated tape usually has a backing of 1 to 10 mils thick, while the adhesive thickness is anywhere from 2 to 5 mils. 

SELF WOUND TAPE

A self-wound tape is a type of tape coated on one side with a pressure-sensitive adhesive and the other side with a release coating. The self-wound tape has no release liner coated with silicone on it. Duct tape, masking tape, and carton sealing tape all qualify as self-wound tape. 

What Kind Of Adhesive Are Used for PSA Tapes?

Adhesive companies primarily use rubber, acrylic, or silicone adhesive to create PSA tape.

RUBBER

Rubber is the least expensive PSA with the fastest sticking ability. Rubber adhesives have natural or synthetic rubbers in them. Companies will formulate those adhesives with resins, oils, and antioxidants. 

Rubber adhesives work best indoors with less stress than an outdoor environment puts on them. They stick to low-surface energy materials, and many engineers formulate rubber adhesives while intending to remove them quickly. 

You can find rubber adhesive on masking tape, carton sealing tape, duct tape, and filament tape. Rubber does not naturally feel tacky, so engineers add resins to create the tacky adhesive needed. 

Natural rubber has a higher molecular weight than synthetic rubber. It sticks well to LSE surfaces. You can remove it cleanly, but it does not do well in the heat and has a short lifespan.

Synthetic rubber is another title for what engineers call "hot melt" adhesives. It is a thermoplastic with a lighter weight and shorter polymer chain than natural rubber. The engineers customize the synthetic rubber, and as a result, it sticks better to surfaces. 

ACRYLIC

Acrylic adhesives hold up better over time. They also tend to resist wear and tear by solvents and the environment. Plus, they can tolerate higher temperatures than rubber adhesives and develop a stronger bond. 

Acrylic adhesives are naturally tacky (i.e., sticky), but engineers endeavor to make them tackier. As for polymers, the ones used for acrylic adhesives are flexible. Developers can adjust them during manufacturing to make the adhesive perform better. 

Solvent acrylic comes from grains dissolved in a solvent. This adhesive does not adhere well to low surface energy plastics. They do stick better, though, than rubber.

Emulsion acrylic comes from spherical particles surrounded by surfactants in a water carrier. Emulsion acrylics cost less and are better for the environment than solvent acrylic adhesives. Their water-based properties make them less moisture resistant, so most people prefer a solvent acrylic. 

Because acrylic lasts longer than other adhesives, people tend to use it indoors and outdoors. 

SILICONE

Neither rubber nor acrylic bonds with silicone as silicone adhesive does.

Silicone adhesives cost more than other adhesives, but they can tolerate very high temperatures and thus handle extreme environments better than other adhesives. 

Many people think silicone adhesives have a low sticking power because they don't bond well initially. It takes time before silicone adhesives can fully bond to a surface.

People typically use tape with silicone adhesive for applications in highly elevated temperatures and caustic environments. You can find silicone adhesives in Teflon tapes, printed circuit board film masking tapes, and silicone release liner splicing tapes. 

Why Use Pressure-Sensitive Tape?

Pressure-sensitive tape is a quick and efficient solution that has become increasingly popular in bonding applications for a variety of reasons. 

Pressure-sensitive tapes are thin and light, making them easy to work with.

Because pressure-sensitive adhesive tape requires no element other than pressure to activate it, it bonds materials quickly. Plus, it can easily bond dissimilar materials. You don’t have to worry about whether the materials are compatible. 

Thus, when you use pressure-sensitive adhesive tape, you can assemble a project quickly since you don’t have to wait for the heat to activate the adhesion or for a solvent. Just press on the tape, and you're good to go!

When you use pressure-sensitive adhesive tape, you can reduce the noise caused by vibrations. Instead of rattling like a traditional fastener, the tape will absorb noise.

Pressure-sensitive adhesive reduces the need to refinish a surface and eliminates traditional visible mechanical fasteners. You'll no longer have a screw or fastener sticking up but rather a smooth finish. 

PSA tape also creates uniform thickness. It can fill gaps and create a more aesthetically pleasing product. 

Which Type of PSA Tape Should I Use? 

When selecting the best type of PSA tape for your job, consider the following criteria: 

1. What surface are you sticking the adhesive to? 
2. What are the conditions that you'll expose the tape to? Will the environment be hot and humid? How windy will it be? 
3. Why are you using this adhesive? What materials does it hold together, and what do you want it to do? 
4. How do you plan to apply your PSA? 
5. Are you using the PSA as a permanent or temporary solution?

Now that you understand the ins and outs of pressure-sensitive adhesive tape, you can start looking for the best tape for the job you have at hand. 

If you’re unsure which tape to use for your application, feel free to contact us for a sample of potential options. However, if you’re not seeking out any particular tapes at the moment, you can learn about more adhesive bonding possibilities in our Learning Center, where we cover design and manufacturing applications for a wide variety of materials. 

Originally published: September 13, 2022